[client] adjust gtk3 version release job (#7163)

- Align default names and reuse same environment variables

- With the uploads now targeting the same stable/yum paths as the GTK4
packages, two packages named netbird-ui with the same version and arch
would collide in the repo indexes. Give the GTK3 variant its own
package name and mark the two as conflicting alternatives.

---------

Co-authored-by: Zoltan Papp <zoltan.pmail@gmail.com>

.goreleaser_ui_gtk3.yaml

@@ -43,19 +43,17 @@ archives:
       - netbird-ui-gtk3
 
 nfpms:
-  # Same package_name as the GTK4 packages -- the two are mutually-exclusive
-  # alternatives served from separate repo paths (see uploads below); a given
-  # distro points at exactly one of them. The file names must still differ:
-  # the Debian pool is shared storage keyed by file name, so a default-named
-  # gtk3 .deb would overwrite the stable one.
+  # Mutually-exclusive alternative to the GTK4 netbird-ui package -- both
+  # ship the same /usr/bin/netbird-ui from the shared stable/yum repos, so
+  # this one carries its own name and conflicts with the GTK4 package.
   - maintainer: Netbird <dev@netbird.io>
     description: Netbird client UI.
     homepage: https://netbird.io/
     license: BSD-3-Clause
     vendor: NetBird
     id: netbird_ui_deb_gtk3
-    package_name: netbird-ui
-    file_name_template: "{{ .PackageName }}-gtk3_{{ .Version }}_{{ .Os }}_{{ .Arch }}"
+    package_name: netbird-ui-gtk3
+    file_name_template: "{{ .PackageName }}_{{ .Version }}_{{ .Os }}_{{ .Arch }}"
     builds:
       - netbird-ui-gtk3
     formats:
@@ -67,6 +65,10 @@ nfpms:
         dst: /usr/share/applications/org.wails.netbird.desktop
       - src: client/ui/build/appicon.png
         dst: /usr/share/pixmaps/netbird.png
+    conflicts:
+      - netbird-ui
+    replaces:
+      - netbird-ui
     dependencies:
       - netbird (>= 0.75.0)
       - libgtk-3-0
@@ -79,8 +81,8 @@ nfpms:
     license: BSD-3-Clause
     vendor: NetBird
     id: netbird_ui_rpm_gtk3
-    package_name: netbird-ui
-    file_name_template: "{{ .PackageName }}-gtk3_{{ .Version }}_{{ .Os }}_{{ .Arch }}"
+    package_name: netbird-ui-gtk3
+    file_name_template: "{{ .PackageName }}_{{ .Version }}_{{ .Os }}_{{ .Arch }}"
     builds:
       - netbird-ui-gtk3
     formats:
@@ -92,6 +94,10 @@ nfpms:
         dst: /usr/share/applications/org.wails.netbird.desktop
       - src: client/ui/build/appicon.png
         dst: /usr/share/pixmaps/netbird.png
+    # No `replaces` here: nfpm maps it to rpm Obsoletes, which would make
+    # dnf swap installed GTK4 netbird-ui packages for this one on upgrade.
+    conflicts:
+      - netbird-ui
     dependencies:
       - netbird >= 0.75.0
       - (gtk3 or libgtk-3-0)
@@ -111,32 +117,20 @@ changelog:
   disable: true
 
 uploads:
-  # The gtk3 packages reuse the netbird-ui package name, so they live in
-  # dedicated repo paths (deb distribution `gtk3`, yum path `yum-gtk3`) that
-  # legacy distros point their repo config at.
-  #
-  # GoReleaser derives the credential env var from the upload name, so these
-  # would look for UPLOAD_DEBIAN-GTK3_SECRET / UPLOAD_YUM-GTK3_SECRET. The
-  # release workflow only exports UPLOAD_DEBIAN_SECRET / UPLOAD_YUM_SECRET, and
-  # a missing secret is a silent skip rather than a failure -- the packages
-  # reached the GitHub release but never the package repositories. Point
-  # `password` at the exported vars so both uploads authenticate.
-  - name: debian-gtk3
+  - name: debian
     skip: "{{ .Env.SKIP_PUBLISH }}"
     ids:
       - netbird_ui_deb_gtk3
     mode: archive
-    target: https://pkgs.wiretrustee.com/debian/pool/{{ .ArtifactName }};deb.distribution=gtk3;deb.component=main;deb.architecture={{ if .Arm }}armhf{{ else }}{{ .Arch }}{{ end }};deb.package=
+    target: https://pkgs.wiretrustee.com/debian/pool/{{ .ArtifactName }};deb.distribution=stable;deb.component=main;deb.architecture={{ if .Arm }}armhf{{ else }}{{ .Arch }}{{ end }};deb.package=
     username: dev@wiretrustee.com
-    password: "{{ .Env.UPLOAD_DEBIAN_SECRET }}"
     method: PUT
 
-  - name: yum-gtk3
+  - name: yum
     skip: "{{ .Env.SKIP_PUBLISH }}"
     ids:
       - netbird_ui_rpm_gtk3
     mode: archive
-    target: https://pkgs.wiretrustee.com/yum-gtk3/{{ .Arch }}{{ if .Arm }}{{ .Arm }}{{ end }}
+    target: https://pkgs.wiretrustee.com/yum/{{ .Arch }}{{ if .Arm }}{{ .Arm }}{{ end }}
     username: dev@wiretrustee.com
-    password: "{{ .Env.UPLOAD_YUM_SECRET }}"
     method: PUT

CONTRIBUTING.md

@@ -112,6 +112,7 @@ aligns with our security standards and design expectations.
         - [Test suite](#test-suite)
     - [Checklist before submitting a PR](#checklist-before-submitting-a-pr)
     - [When we close a PR](#when-we-close-a-pr)
+    - [Translations](#translations)
     - [Other project repositories](#other-project-repositories)
     - [Contributor License Agreement](#contributor-license-agreement)
 
@@ -612,6 +613,17 @@ A closed PR is not a rejected idea. Take it back to the
 [discussion](https://github.com/netbirdio/netbird/discussions), settle the
 approach, and reopen the work from there.
 
+## Translations
+
+Desktop UI translations are not contributed through pull requests. Translate on
+[Crowdin](https://crowdin.com/project/netbird) instead: no ticket needed, just
+join the project and pick your language. Crowdin syncs with this repository and
+opens the service PRs itself, so hand-edited locale files would conflict with
+the next sync. Style, terminology, and review guidance live in
+[client/ui/i18n/TRANSLATING.md](client/ui/i18n/TRANSLATING.md). To request a
+language the project does not offer yet, ask on the Crowdin project page or in
+a [discussion](https://github.com/netbirdio/netbird/discussions).
+
 ## Other project repositories
 
 NetBird project is composed of 3 main repositories:

client/ssh/server/command_execution_windows.go

@@ -243,7 +243,7 @@ func (s *Server) setUserEnvironmentVariables(envMap map[string]string, userProfi
 
 // prepareCommandEnv prepares environment variables for command execution on Windows
 func (s *Server) prepareCommandEnv(logger *log.Entry, localUser *user.User, session ssh.Session) []string {
-	username, domain := s.parseUsername(localUser.Username)
+	username, domain := parseUsername(localUser.Username)
 	userEnv, err := s.getUserEnvironment(logger, username, domain)
 	if err != nil {
 		log.Debugf("failed to get user environment for %s\\%s, using fallback: %v", domain, username, err)
@@ -383,7 +383,7 @@ func (s *Server) executeCommandWithPty(logger *log.Entry, session ssh.Session, _
 		return false
 	}
 
-	username, domain := s.parseUsername(localUser.Username)
+	username, domain := parseUsername(localUser.Username)
 	shell := getUserShell(localUser.Uid)
 
 	req := PtyExecutionRequest{

client/ssh/server/port_forwarding.go

@@ -133,7 +133,12 @@ func (s *Server) checkPrivilegedPortAccess(forwardType string, port uint32, resu
 		return nil
 	}
 
-	if result.User != nil && isPrivilegedUsername(result.User.Username) {
+	// Only uid 0 may bind below the threshold, which is the kernel's own rule and
+	// is asked directly rather than through isPrivilegedOrUnknown: that helper
+	// reports an account it cannot evaluate as privileged, which is safe for a
+	// refusal and unsafe for a grant such as this one. Windows has returned
+	// above, so Uid here is a Unix uid and never a SID.
+	if result.User != nil && result.User.Uid == "0" {
 		return nil
 	}
 

client/ssh/server/privileges_other.go

@@ -0,0 +1,16 @@
+//go:build !windows
+
+package server
+
+// isProcessElevated is only meaningful on Windows; other platforms use the
+// effective UID check in isCurrentProcessPrivileged.
+func isProcessElevated() bool {
+	return false
+}
+
+// isWindowsAccountPrivilegedOrUnknown is only reachable on Windows. Report
+// privileged on other platforms so a caller refusing privileged accounts fails
+// closed.
+func isWindowsAccountPrivilegedOrUnknown(string) bool {
+	return true
+}

client/ssh/server/privileges_windows.go

@@ -0,0 +1,228 @@
+//go:build windows
+
+package server
+
+import (
+	"fmt"
+	"strings"
+	"unsafe"
+
+	log "github.com/sirupsen/logrus"
+	"golang.org/x/sys/windows"
+)
+
+var (
+	netapi32                  = windows.NewLazySystemDLL("netapi32.dll")
+	procNetUserGetLocalGroups = netapi32.NewProc("NetUserGetLocalGroups")
+)
+
+const (
+	// lgIncludeIndirect makes NetUserGetLocalGroups also return local groups
+	// the user belongs to through a global group.
+	lgIncludeIndirect  = 0x1
+	maxPreferredLength = 0xFFFFFFFF
+)
+
+// localGroupUsersInfo0 mirrors LOCALGROUP_USERS_INFO_0.
+type localGroupUsersInfo0 struct {
+	name *uint16
+}
+
+// isProcessElevated reports whether the current process token is elevated
+// (TokenElevation): true for elevated administrators, the built-in
+// Administrator, administrators with UAC disabled, and SYSTEM; false for
+// standard users and administrators running with a UAC-filtered token.
+func isProcessElevated() bool {
+	return windows.GetCurrentProcessToken().IsElevated()
+}
+
+// isWindowsAccountPrivilegedOrUnknown reports whether the account is privileged
+// on this machine: a well-known service account, a built-in Administrator
+// (RID 500), or a member of the local Administrators group, directly or through
+// nested groups.
+//
+// An account whose privilege cannot be determined counts as privileged, which
+// is why the name says "or unknown". That is fail-closed for a caller that
+// refuses privileged accounts, and fail-open for a caller that grants something
+// to them, so only the former may use this.
+func isWindowsAccountPrivilegedOrUnknown(username string) bool {
+	sid, _, _, err := windows.LookupSID("", username)
+	if err != nil {
+		log.Warnf("privilege check: SID lookup for %q failed, treating as privileged: %v", username, err)
+		return true
+	}
+
+	if isPrivilegedUserSID(sid) {
+		return true
+	}
+
+	member, err := isLocalAdminsMember(username)
+	if err != nil {
+		log.Warnf("privilege check: cannot determine Administrators membership for %q, treating as privileged: %v", username, err)
+		return true
+	}
+	return member
+}
+
+// isPrivilegedUserSID reports whether the SID itself identifies a privileged
+// principal, without consulting group membership.
+func isPrivilegedUserSID(sid *windows.SID) bool {
+	wellKnown := []windows.WELL_KNOWN_SID_TYPE{
+		windows.WinLocalSystemSid,
+		windows.WinLocalServiceSid,
+		windows.WinNetworkServiceSid,
+		windows.WinBuiltinAdministratorsSid,
+	}
+	for _, sidType := range wellKnown {
+		if sid.IsWellKnown(sidType) {
+			return true
+		}
+	}
+	return isBuiltinAdministratorSID(sid)
+}
+
+// isBuiltinAdministratorSID reports whether the SID is a machine or domain
+// built-in Administrator account (S-1-5-21-...-500). RID 500 is reserved for
+// that account; it can be renamed but cannot be removed from the
+// Administrators group.
+func isBuiltinAdministratorSID(sid *windows.SID) bool {
+	if sid.IdentifierAuthority() != windows.SECURITY_NT_AUTHORITY {
+		return false
+	}
+	count := sid.SubAuthorityCount()
+	if count < 2 || sid.SubAuthority(0) != 21 {
+		return false
+	}
+	return sid.SubAuthority(uint32(count-1)) == 500
+}
+
+// isLocalAdminsMember reports whether the account is a member of the local
+// Administrators group.
+//
+// Local accounts are checked against the local SAM, which is authoritative for
+// them and, unlike a token, cannot under-report: UAC filters the tokens of
+// local administrators, and a filtered token carries Administrators as
+// deny-only, which a membership check on the token would read as "not a
+// member". Domain accounts are exempt from that filtering, so for them an S4U
+// token is preferred because its group list is LSA's transitive expansion and
+// therefore covers nested and universal groups plus the machine's own local
+// groups. NetUserGetLocalGroups expands only one global-group hop but needs no
+// logon, so it serves as the fallback when no token can be obtained.
+func isLocalAdminsMember(username string) (bool, error) {
+	adminSid, err := windows.CreateWellKnownSid(windows.WinBuiltinAdministratorsSid)
+	if err != nil {
+		return false, fmt.Errorf("create Administrators SID: %w", err)
+	}
+
+	account, domain := parseUsername(username)
+	if NewPrivilegeDropper().isLocalUser(domain) {
+		return localGroupsContainSID(account, adminSid)
+	}
+
+	member, s4uErr := s4uTokenIsMember(account, domain, adminSid)
+	if s4uErr == nil {
+		return member, nil
+	}
+	log.Debugf("privilege check: S4U membership check for %q failed, falling back to local group enumeration: %v", username, s4uErr)
+
+	member, err = localGroupsContainSID(buildUserCpn(account, domain), adminSid)
+	if err != nil {
+		return false, fmt.Errorf("S4U check: %w; local group enumeration: %w", s4uErr, err)
+	}
+	return member, nil
+}
+
+// s4uTokenIsMember obtains an S4U token for the account and checks whether the
+// given SID is enabled in it.
+func s4uTokenIsMember(account, domain string, sid *windows.SID) (bool, error) {
+	token, err := generateS4UUserToken(log.NewEntry(log.StandardLogger()), account, domain)
+	if err != nil {
+		return false, err
+	}
+	defer func() {
+		if err := windows.CloseHandle(token); err != nil {
+			log.Debugf("close S4U token: %v", err)
+		}
+	}()
+	return windows.Token(token).IsMember(sid)
+}
+
+// localGroupsContainSID reports whether the wanted group is among the local
+// groups the account belongs to, directly or through a global group.
+//
+// The wanted SID is resolved to its group name once and compared against the
+// enumerated names. Well-known SIDs resolve from a static table, so that lookup
+// needs no domain controller, and it keeps the comparison correct for a renamed
+// or localized group because both sides then carry the new name. Resolving each
+// enumerated name back to a SID instead would add a lookup per group that can
+// block until it times out while a domain controller is unreachable, and cannot
+// change the outcome: the names enumerated here are local groups of this
+// machine, whose names are unique, so a name match identifies the group.
+//
+// A failure to resolve the wanted SID is returned rather than reported as
+// "not a member", so a privilege check built on this fails closed.
+func localGroupsContainSID(username string, want *windows.SID) (bool, error) {
+	wantName, _, _, err := want.LookupAccount("")
+	if err != nil {
+		return false, fmt.Errorf("resolve group SID %s to a name: %w", want, err)
+	}
+
+	groups, err := netUserGetLocalGroups(username)
+	if err != nil {
+		return false, err
+	}
+
+	for _, group := range groups {
+		if strings.EqualFold(group, wantName) {
+			return true, nil
+		}
+	}
+	return false, nil
+}
+
+// netUserGetLocalGroups returns the names of the local groups the account is a
+// member of, including indirect membership through global groups.
+func netUserGetLocalGroups(username string) ([]string, error) {
+	name16, err := windows.UTF16PtrFromString(username)
+	if err != nil {
+		return nil, fmt.Errorf("convert username: %w", err)
+	}
+
+	var buf *byte
+	var entriesRead, totalEntries uint32
+	status, _, _ := procNetUserGetLocalGroups.Call(
+		0, // local server
+		uintptr(unsafe.Pointer(name16)),
+		0, // level 0: LOCALGROUP_USERS_INFO_0
+		lgIncludeIndirect,
+		uintptr(unsafe.Pointer(&buf)),
+		maxPreferredLength,
+		uintptr(unsafe.Pointer(&entriesRead)),
+		uintptr(unsafe.Pointer(&totalEntries)),
+	)
+	if status != 0 {
+		return nil, fmt.Errorf("NetUserGetLocalGroups for %q: status %d", username, status)
+	}
+	if buf == nil {
+		return nil, nil
+	}
+	defer func() {
+		if err := windows.NetApiBufferFree(buf); err != nil {
+			log.Debugf("free NetApi buffer: %v", err)
+		}
+	}()
+
+	// MAX_PREFERRED_LENGTH makes the API allocate as much as it needs, so a
+	// short read is not expected. Report it rather than silently returning a
+	// subset of the account's groups.
+	if entriesRead != totalEntries {
+		return nil, fmt.Errorf("NetUserGetLocalGroups for %q returned %d of %d groups", username, entriesRead, totalEntries)
+	}
+
+	entries := unsafe.Slice((*localGroupUsersInfo0)(unsafe.Pointer(buf)), entriesRead)
+	groups := make([]string, 0, entriesRead)
+	for _, entry := range entries {
+		groups = append(groups, windows.UTF16PtrToString(entry.name))
+	}
+	return groups, nil
+}

client/ssh/server/privileges_windows_test.go

@@ -0,0 +1,293 @@
+//go:build windows
+
+package server
+
+import (
+	"os/user"
+	"testing"
+	"unsafe"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"golang.org/x/sys/windows"
+)
+
+// filterNormalAccount limits NetUserEnum to normal user accounts.
+const filterNormalAccount = 0x2
+
+// TOKEN_ELEVATION_TYPE values.
+const (
+	tokenElevationTypeDefault = 1
+	tokenElevationTypeFull    = 2
+	tokenElevationTypeLimited = 3
+)
+
+// tokenElevationType reads TokenElevationType from a token.
+func tokenElevationType(token windows.Token) (uint32, error) {
+	var elevationType, returnedLen uint32
+	err := windows.GetTokenInformation(token, windows.TokenElevationType,
+		(*byte)(unsafe.Pointer(&elevationType)), uint32(unsafe.Sizeof(elevationType)), &returnedLen)
+	if err != nil {
+		return 0, err
+	}
+	return elevationType, nil
+}
+
+// userInfo0 mirrors USER_INFO_0.
+type userInfo0 struct {
+	name *uint16
+}
+
+func mustParseSID(t *testing.T, s string) *windows.SID {
+	t.Helper()
+	sid, err := windows.StringToSid(s)
+	require.NoError(t, err, "parse SID %s", s)
+	return sid
+}
+
+// localAccountNames returns the names of the local user accounts.
+func localAccountNames(t *testing.T) []string {
+	t.Helper()
+
+	var buf *byte
+	var entriesRead, totalEntries, resume uint32
+	err := windows.NetUserEnum(nil, 0, filterNormalAccount, &buf, maxPreferredLength,
+		&entriesRead, &totalEntries, &resume)
+	require.NoError(t, err, "enumerate local users")
+	t.Cleanup(func() {
+		require.NoError(t, windows.NetApiBufferFree(buf), "free NetApi buffer")
+	})
+
+	entries := unsafe.Slice((*userInfo0)(unsafe.Pointer(buf)), entriesRead)
+	names := make([]string, 0, entriesRead)
+	for _, entry := range entries {
+		names = append(names, windows.UTF16PtrToString(entry.name))
+	}
+	return names
+}
+
+// localAccountNameByRID returns the name of the local account carrying the
+// given RID. Accounts such as Administrator and Guest can be renamed and are
+// localized, so tests must not name them literally.
+func localAccountNameByRID(t *testing.T, rid uint32) string {
+	t.Helper()
+
+	for _, name := range localAccountNames(t) {
+		sid, _, _, err := windows.LookupSID("", name)
+		if err != nil {
+			continue
+		}
+		if sid.IdentifierAuthority() != windows.SECURITY_NT_AUTHORITY {
+			continue
+		}
+		count := sid.SubAuthorityCount()
+		if count < 2 || sid.SubAuthority(0) != 21 {
+			continue
+		}
+		if sid.SubAuthority(uint32(count-1)) == rid {
+			return name
+		}
+	}
+
+	t.Fatalf("no local account with RID %d", rid)
+	return ""
+}
+
+// wellKnownAccountName resolves a well-known SID to the qualified account name
+// the local system uses for it, which is localized.
+func wellKnownAccountName(t *testing.T, sidType windows.WELL_KNOWN_SID_TYPE) string {
+	t.Helper()
+
+	sid, err := windows.CreateWellKnownSid(sidType)
+	require.NoError(t, err, "create well-known SID")
+	name, domain, _, err := sid.LookupAccount("")
+	require.NoError(t, err, "resolve %s to an account name", sid)
+	if domain == "" {
+		return name
+	}
+	return domain + `\` + name
+}
+
+func TestIsBuiltinAdministratorSID(t *testing.T) {
+	tests := []struct {
+		name string
+		sid  string
+		want bool
+	}{
+		{"machine_administrator", "S-1-5-21-1111111111-2222222222-3333333333-500", true},
+		{"domain_administrator", "S-1-5-21-3390233681-4087452608-412898826-500", true},
+		{"regular_user", "S-1-5-21-1111111111-2222222222-3333333333-1001", false},
+		{"guest_account", "S-1-5-21-1111111111-2222222222-3333333333-501", false},
+		{"domain_admins_group", "S-1-5-21-1111111111-2222222222-3333333333-512", false},
+		{"system", "S-1-5-18", false},
+		{"administrators_group", "S-1-5-32-544", false},
+		{"non_nt_authority", "S-1-1-0", false},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := isBuiltinAdministratorSID(mustParseSID(t, tt.sid))
+			assert.Equal(t, tt.want, result, "RID 500 detection for %s", tt.sid)
+		})
+	}
+}
+
+func TestIsPrivilegedUserSID(t *testing.T) {
+	tests := []struct {
+		name string
+		sid  string
+		want bool
+	}{
+		{"local_system", "S-1-5-18", true},
+		{"local_service", "S-1-5-19", true},
+		{"network_service", "S-1-5-20", true},
+		{"administrators_group", "S-1-5-32-544", true},
+		{"builtin_administrator", "S-1-5-21-1111111111-2222222222-3333333333-500", true},
+		{"regular_user", "S-1-5-21-1111111111-2222222222-3333333333-1001", false},
+		{"users_group", "S-1-5-32-545", false},
+		{"everyone", "S-1-1-0", false},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := isPrivilegedUserSID(mustParseSID(t, tt.sid))
+			assert.Equal(t, tt.want, result, "SID privilege classification for %s", tt.sid)
+		})
+	}
+}
+
+func TestIsWindowsAccountPrivilegedOrUnknown(t *testing.T) {
+	tests := []struct {
+		name     string
+		username string
+		want     bool
+	}{
+		{"system", wellKnownAccountName(t, windows.WinLocalSystemSid), true},
+		{"local_service", wellKnownAccountName(t, windows.WinLocalServiceSid), true},
+		{"network_service", wellKnownAccountName(t, windows.WinNetworkServiceSid), true},
+		{"administrators_group", wellKnownAccountName(t, windows.WinBuiltinAdministratorsSid), true},
+		// The built-in Administrator (RID 500) and Guest (RID 501) accounts
+		// exist on every Windows installation, though they may be disabled.
+		{"builtin_administrator", localAccountNameByRID(t, 500), true},
+		{"guest", localAccountNameByRID(t, 501), false},
+		// Unresolvable accounts fail closed.
+		{"nonexistent_user", "netbird-no-such-user", true},
+		{"empty_username", "", true},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := isWindowsAccountPrivilegedOrUnknown(tt.username)
+			assert.Equal(t, tt.want, result, "account privilege classification for %q", tt.username)
+		})
+	}
+}
+
+func TestIsProcessElevated(t *testing.T) {
+	elevated := isProcessElevated()
+
+	// TokenElevationType is a second, independent view of the same token:
+	// Full means elevated and Limited means a filtered administrator, while
+	// Default covers both a standard user and an administrator with no linked
+	// token (UAC off, the built-in Administrator, SYSTEM), so it implies nothing.
+	elevationType, err := tokenElevationType(windows.GetCurrentProcessToken())
+	require.NoError(t, err, "read token elevation type")
+
+	adminSid, err := windows.CreateWellKnownSid(windows.WinBuiltinAdministratorsSid)
+	require.NoError(t, err, "create Administrators SID")
+
+	// Token(0) makes CheckTokenMembership evaluate the caller's own token. It
+	// counts only enabled SIDs, so a filtered administrator reports false here.
+	member, err := windows.Token(0).IsMember(adminSid)
+	require.NoError(t, err, "check own Administrators membership")
+
+	t.Logf("elevated=%v elevationType=%d memberOfAdministrators=%v", elevated, elevationType, member)
+
+	switch elevationType {
+	case tokenElevationTypeFull:
+		assert.True(t, elevated, "a token of elevation type Full must report elevated")
+	case tokenElevationTypeLimited:
+		assert.False(t, elevated, "a filtered administrator token must not report elevated")
+	}
+
+	// Administrators enabled in the token means the token wields administrative
+	// rights, which is what elevation reports.
+	if member {
+		assert.True(t, elevated, "token with enabled Administrators membership must report elevated")
+	}
+}
+
+// TestS4UMembershipAgreesWithLocalGroups exercises the S4U token path used
+// for domain accounts. S4U logons need the TCB privilege, so the test runs
+// only as SYSTEM (which is how CI executes the suite). For local accounts the
+// token's Administrators membership must agree with the SAM enumeration.
+func TestS4UMembershipAgreesWithLocalGroups(t *testing.T) {
+	system, err := windows.CreateWellKnownSid(windows.WinLocalSystemSid)
+	require.NoError(t, err, "create SYSTEM SID")
+	current, err := user.Current()
+	require.NoError(t, err, "get current user")
+	if current.Uid != system.String() {
+		t.Skipf("S4U logon requires SYSTEM (running as %s)", current.Username)
+	}
+
+	adminSid, err := windows.CreateWellKnownSid(windows.WinBuiltinAdministratorsSid)
+	require.NoError(t, err, "create Administrators SID")
+
+	checked := 0
+	for _, name := range localAccountNames(t) {
+		viaToken, err := s4uTokenIsMember(name, ".", adminSid)
+		if err != nil {
+			// Disabled or logon-restricted accounts cannot get an S4U logon.
+			t.Logf("skipping %s: %v", name, err)
+			continue
+		}
+		viaSAM, err := localGroupsContainSID(name, adminSid)
+		require.NoError(t, err, "enumerate local groups for %s", name)
+
+		assert.Equal(t, viaSAM, viaToken, "S4U token and SAM enumeration must agree on Administrators membership for %s", name)
+		checked++
+	}
+	// Ineligible accounts are skipped, so without this the test could report
+	// success while comparing nothing at all.
+	require.Positive(t, checked, "no local account completed an S4U logon, so nothing was compared")
+	t.Logf("checked %d local accounts via S4U", checked)
+}
+
+// TestLocalGroupsContainSID_Administrator checks the positive case against the
+// built-in Administrator, a member of Administrators on every installation.
+func TestLocalGroupsContainSID_Administrator(t *testing.T) {
+	adminSid, err := windows.CreateWellKnownSid(windows.WinBuiltinAdministratorsSid)
+	require.NoError(t, err, "create Administrators SID")
+
+	administrator := localAccountNameByRID(t, 500)
+	member, err := localGroupsContainSID(administrator, adminSid)
+	require.NoError(t, err, "enumerate local groups for %s", administrator)
+	assert.True(t, member, "%s is a member of the Administrators group", administrator)
+}
+
+// TestLocalGroupsContainSID_UnresolvableGroupFailsClosed covers a wanted SID
+// that resolves to no group: the error must surface rather than being reported
+// as "not a member", so the privilege check treats the account as privileged.
+func TestLocalGroupsContainSID_UnresolvableGroupFailsClosed(t *testing.T) {
+	unknown := mustParseSID(t, "S-1-5-21-1111111111-2222222222-3333333333-4444")
+
+	_, err := localGroupsContainSID(localAccountNameByRID(t, 500), unknown)
+	require.Error(t, err, "must report an error when the wanted group cannot be identified")
+}
+
+func TestLocalGroupsContainSID_Guest(t *testing.T) {
+	guestsSid, err := windows.CreateWellKnownSid(windows.WinBuiltinGuestsSid)
+	require.NoError(t, err, "create Guests SID")
+	adminsSid, err := windows.CreateWellKnownSid(windows.WinBuiltinAdministratorsSid)
+	require.NoError(t, err, "create Administrators SID")
+
+	guest := localAccountNameByRID(t, 501)
+
+	inGuests, err := localGroupsContainSID(guest, guestsSid)
+	require.NoError(t, err, "enumerate local groups for %s", guest)
+	assert.True(t, inGuests, "%s is a member of the Guests group", guest)
+
+	inAdmins, err := localGroupsContainSID(guest, adminsSid)
+	require.NoError(t, err, "enumerate local groups for %s", guest)
+	assert.False(t, inAdmins, "%s is not a member of the Administrators group", guest)
+}

client/ssh/server/server_config_test.go

@@ -239,6 +239,7 @@ func TestServer_PrivilegedPortAccess(t *testing.T) {
 		forwardType   string
 		port          uint32
 		username      string
+		uid           string
 		expectError   bool
 		errorMsg      string
 		skipOnWindows bool
@@ -248,6 +249,7 @@ func TestServer_PrivilegedPortAccess(t *testing.T) {
 			forwardType:   "remote",
 			port:          80,
 			username:      "testuser",
+			uid:           "1000",
 			expectError:   true,
 			errorMsg:      "cannot bind to privileged port",
 			skipOnWindows: true,
@@ -257,6 +259,7 @@ func TestServer_PrivilegedPortAccess(t *testing.T) {
 			forwardType:   "tcpip-forward",
 			port:          443,
 			username:      "testuser",
+			uid:           "1000",
 			expectError:   true,
 			errorMsg:      "cannot bind to privileged port",
 			skipOnWindows: true,
@@ -266,6 +269,7 @@ func TestServer_PrivilegedPortAccess(t *testing.T) {
 			forwardType: "remote",
 			port:        8080,
 			username:    "testuser",
+			uid:         "1000",
 			expectError: false,
 		},
 		{
@@ -273,6 +277,7 @@ func TestServer_PrivilegedPortAccess(t *testing.T) {
 			forwardType: "remote",
 			port:        0,
 			username:    "testuser",
+			uid:         "1000",
 			expectError: false,
 		},
 		{
@@ -280,13 +285,35 @@ func TestServer_PrivilegedPortAccess(t *testing.T) {
 			forwardType: "remote",
 			port:        22,
 			username:    "root",
+			uid:         "0",
 			expectError: false,
 		},
+		{
+			// Only uid 0 is privileged, whatever the account is called.
+			name:          "uid 0 under another name may bind a privileged port",
+			forwardType:   "remote",
+			port:          22,
+			username:      "toor",
+			uid:           "0",
+			expectError:   false,
+			skipOnWindows: true,
+		},
+		{
+			name:          "account named root without uid 0 may not",
+			forwardType:   "remote",
+			port:          22,
+			username:      "root",
+			uid:           "1000",
+			expectError:   true,
+			errorMsg:      "cannot bind to privileged port",
+			skipOnWindows: true,
+		},
 		{
 			name:        "local forward privileged port allowed for non-root",
 			forwardType: "local",
 			port:        80,
 			username:    "testuser",
+			uid:         "1000",
 			expectError: false,
 		},
 	}
@@ -299,7 +326,7 @@ func TestServer_PrivilegedPortAccess(t *testing.T) {
 
 			result := PrivilegeCheckResult{
 				Allowed: true,
-				User:    &user.User{Username: tt.username},
+				User:    &user.User{Username: tt.username, Uid: tt.uid},
 			}
 
 			err := server.checkPrivilegedPortAccess(tt.forwardType, tt.port, result)
@@ -420,6 +447,13 @@ func TestServer_PortConflictHandling(t *testing.T) {
 
 func TestServer_IsPrivilegedUser(t *testing.T) {
 
+	// Windows classification depends on account SIDs and group membership, and
+	// the accounts involved carry localized, renameable names. It is covered by
+	// TestIsWindowsAccountPrivileged, which resolves them from well-known SIDs.
+	if runtime.GOOS == "windows" {
+		t.Skip("covered by TestIsWindowsAccountPrivileged")
+	}
+
 	tests := []struct {
 		username    string
 		expected    bool
@@ -440,44 +474,16 @@ func TestServer_IsPrivilegedUser(t *testing.T) {
 			expected:    false,
 			description: "empty username should not be privileged",
 		},
-	}
-
-	// Add Windows-specific tests
-	if runtime.GOOS == "windows" {
-		tests = append(tests, []struct {
-			username    string
-			expected    bool
-			description string
-		}{
-			{
-				username:    "Administrator",
-				expected:    true,
-				description: "Administrator should be considered privileged on Windows",
-			},
-			{
-				username:    "administrator",
-				expected:    true,
-				description: "administrator should be considered privileged on Windows (case insensitive)",
-			},
-		}...)
-	} else {
-		// On non-Windows systems, Administrator should not be privileged
-		tests = append(tests, []struct {
-			username    string
-			expected    bool
-			description string
-		}{
-			{
-				username:    "Administrator",
-				expected:    false,
-				description: "Administrator should not be privileged on non-Windows systems",
-			},
-		}...)
+		{
+			username:    "Administrator",
+			expected:    false,
+			description: "Administrator should not be privileged on non-Windows systems",
+		},
 	}
 
 	for _, tt := range tests {
 		t.Run(tt.description, func(t *testing.T) {
-			result := isPrivilegedUsername(tt.username)
+			result := isPrivilegedOrUnknown(tt.username)
 			assert.Equal(t, tt.expected, result, tt.description)
 		})
 	}

client/ssh/server/sftp_windows.go

@@ -17,7 +17,7 @@ import (
 // createSftpCommand creates a Windows SFTP command with user switching.
 // The caller must close the returned token handle after starting the process.
 func (s *Server) createSftpCommand(targetUser *user.User, sess ssh.Session) (*exec.Cmd, windows.Token, error) {
-	username, domain := s.parseUsername(targetUser.Username)
+	username, domain := parseUsername(targetUser.Username)
 
 	netbirdPath, err := os.Executable()
 	if err != nil {

client/ssh/server/user_utils.go

@@ -16,11 +16,6 @@ var (
 	ErrPrivilegedUserSwitch = errors.New("cannot switch to privileged user - current user lacks required privileges")
 )
 
-// isPlatformUnix returns true for Unix-like platforms (Linux, macOS, etc.)
-func isPlatformUnix() bool {
-	return getCurrentOS() != "windows"
-}
-
 // Dependency injection variables for testing - allows mocking dynamic runtime checks
 var (
 	getCurrentUser         = currentUserWithGetent
@@ -29,6 +24,9 @@ var (
 	getIsProcessPrivileged = isCurrentProcessPrivileged
 
 	getEuid = os.Geteuid
+
+	getProcessElevated                   = isProcessElevated
+	getWindowsAccountPrivilegedOrUnknown = isWindowsAccountPrivilegedOrUnknown
 )
 
 const (
@@ -65,6 +63,13 @@ type PrivilegeCheckResult struct {
 	RequiresUserSwitching bool
 }
 
+// privilegeCheckContext holds all context needed for privilege checking
+type privilegeCheckContext struct {
+	currentUser           *user.User
+	currentUserPrivileged bool
+	allowRoot             bool
+}
+
 // CheckPrivileges performs comprehensive privilege checking for all SSH features.
 // This is the single source of truth for privilege decisions across the SSH server.
 func (s *Server) CheckPrivileges(req PrivilegeCheckRequest) PrivilegeCheckResult {
@@ -75,7 +80,7 @@ func (s *Server) CheckPrivileges(req PrivilegeCheckRequest) PrivilegeCheckResult
 
 	// Handle empty username case - but still check root access controls
 	if req.RequestedUsername == "" {
-		if isPrivilegedUsername(context.currentUser.Username) && !context.allowRoot {
+		if isPrivilegedOrUnknown(context.currentUser.Username) && !context.allowRoot {
 			return PrivilegeCheckResult{
 				Allowed: false,
 				Error:   &PrivilegedUserError{Username: context.currentUser.Username},
@@ -135,7 +140,7 @@ func (s *Server) checkUserRequest(ctx *privilegeCheckContext, req PrivilegeCheck
 
 	needsUserSwitching := !isSameResolvedUser(resolvedUser, ctx.currentUser)
 
-	if isPrivilegedUsername(resolvedUser.Username) && !ctx.allowRoot {
+	if isPrivilegedOrUnknown(resolvedUser.Username) && !ctx.allowRoot {
 		return PrivilegeCheckResult{
 			Allowed:               false,
 			Error:                 &PrivilegedUserError{Username: resolvedUser.Username},
@@ -175,6 +180,42 @@ func (s *Server) resolveRequestedUser(requestedUsername string) (*user.User, err
 	return u, nil
 }
 
+// SetAllowRootLogin configures root login access
+func (s *Server) SetAllowRootLogin(allow bool) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	s.allowRootLogin = allow
+}
+
+// userNameLookup performs user lookup with root login permission check
+func (s *Server) userNameLookup(username string) (*user.User, error) {
+	result, err := s.userPrivilegeCheck(username)
+	if err != nil {
+		return nil, err
+	}
+	return result.User, nil
+}
+
+// userPrivilegeCheck performs user lookup with full privilege check result
+func (s *Server) userPrivilegeCheck(username string) (PrivilegeCheckResult, error) {
+	result := s.CheckPrivileges(PrivilegeCheckRequest{
+		RequestedUsername:         username,
+		FeatureSupportsUserSwitch: true,
+		FeatureName:               FeatureSSHLogin,
+	})
+
+	if !result.Allowed {
+		return result, result.Error
+	}
+
+	return result, nil
+}
+
+// isPlatformUnix returns true for Unix-like platforms (Linux, macOS, etc.)
+func isPlatformUnix() bool {
+	return getCurrentOS() != "windows"
+}
+
 // isSameResolvedUser compares two resolved user identities
 func isSameResolvedUser(user1, user2 *user.User) bool {
 	if user1 == nil || user2 == nil {
@@ -183,13 +224,6 @@ func isSameResolvedUser(user1, user2 *user.User) bool {
 	return user1.Uid == user2.Uid
 }
 
-// privilegeCheckContext holds all context needed for privilege checking
-type privilegeCheckContext struct {
-	currentUser           *user.User
-	currentUserPrivileged bool
-	allowRoot             bool
-}
-
 // isSameUser checks if two usernames refer to the same user
 // SECURITY: This function must be conservative - it should only return true
 // when we're certain both usernames refer to the exact same user identity
@@ -253,159 +287,30 @@ func isWindowsSameUser(requestedUsername, currentUsername string) bool {
 	return strings.EqualFold(reqDomain, curDomain)
 }
 
-// SetAllowRootLogin configures root login access
-func (s *Server) SetAllowRootLogin(allow bool) {
-	s.mu.Lock()
-	defer s.mu.Unlock()
-	s.allowRootLogin = allow
-}
-
-// userNameLookup performs user lookup with root login permission check
-func (s *Server) userNameLookup(username string) (*user.User, error) {
-	result := s.CheckPrivileges(PrivilegeCheckRequest{
-		RequestedUsername:         username,
-		FeatureSupportsUserSwitch: true,
-		FeatureName:               FeatureSSHLogin,
-	})
-
-	if !result.Allowed {
-		return nil, result.Error
-	}
-
-	return result.User, nil
-}
-
-// userPrivilegeCheck performs user lookup with full privilege check result
-func (s *Server) userPrivilegeCheck(username string) (PrivilegeCheckResult, error) {
-	result := s.CheckPrivileges(PrivilegeCheckRequest{
-		RequestedUsername:         username,
-		FeatureSupportsUserSwitch: true,
-		FeatureName:               FeatureSSHLogin,
-	})
-
-	if !result.Allowed {
-		return result, result.Error
-	}
-
-	return result, nil
-}
-
-// isPrivilegedUsername checks if the given username represents a privileged user across platforms.
-// On Unix: root
-// On Windows: Administrator, SYSTEM (case-insensitive)
-// Handles domain-qualified usernames like "DOMAIN\Administrator" or "user@domain.com"
-func isPrivilegedUsername(username string) bool {
+// isPrivilegedOrUnknown reports whether the given username represents a
+// privileged user, or on Windows an account whose privilege could not be
+// determined.
+// On Unix: root.
+// On Windows: well-known service accounts, built-in Administrator accounts,
+// and members of the local Administrators group; handles domain-qualified
+// usernames like "DOMAIN\user" or "user@domain.com". An account that cannot be
+// resolved or evaluated is reported as privileged.
+//
+// Use this to refuse privileged accounts, never to grant them anything: the
+// undetermined case is safe for a refusal and unsafe for a grant.
+func isPrivilegedOrUnknown(username string) bool {
 	if getCurrentOS() != "windows" {
 		return username == "root"
 	}
-
-	bareUsername := username
-	// Handle Windows domain format: DOMAIN\username
-	if idx := strings.LastIndex(username, `\`); idx != -1 {
-		bareUsername = username[idx+1:]
-	}
-	// Handle email-style format: username@domain.com
-	if idx := strings.Index(bareUsername, "@"); idx != -1 {
-		bareUsername = bareUsername[:idx]
-	}
-
-	return isWindowsPrivilegedUser(bareUsername)
-}
-
-// isWindowsPrivilegedUser checks if a bare username (domain already stripped) represents a Windows privileged account
-func isWindowsPrivilegedUser(bareUsername string) bool {
-	// common privileged usernames (case insensitive)
-	privilegedNames := []string{
-		"administrator",
-		"admin",
-		"root",
-		"system",
-		"localsystem",
-		"networkservice",
-		"localservice",
-	}
-
-	usernameLower := strings.ToLower(bareUsername)
-	for _, privilegedName := range privilegedNames {
-		if usernameLower == privilegedName {
-			return true
-		}
-	}
-
-	// computer accounts (ending with $) are not privileged by themselves
-	// They only gain privileges through group membership or specific SIDs
-
-	if targetUser, err := lookupUser(bareUsername); err == nil {
-		return isWindowsPrivilegedSID(targetUser.Uid)
-	}
-
-	return false
-}
-
-// isWindowsPrivilegedSID checks if a Windows SID represents a privileged account
-func isWindowsPrivilegedSID(sid string) bool {
-	privilegedSIDs := []string{
-		"S-1-5-18",     // Local System (SYSTEM)
-		"S-1-5-19",     // Local Service (NT AUTHORITY\LOCAL SERVICE)
-		"S-1-5-20",     // Network Service (NT AUTHORITY\NETWORK SERVICE)
-		"S-1-5-32-544", // Administrators group (BUILTIN\Administrators)
-		"S-1-5-500",    // Built-in Administrator account (local machine RID 500)
-	}
-
-	for _, privilegedSID := range privilegedSIDs {
-		if sid == privilegedSID {
-			return true
-		}
-	}
-
-	// Check for domain administrator accounts (RID 500 in any domain)
-	// Format: S-1-5-21-domain-domain-domain-500
-	// This is reliable as RID 500 is reserved for the domain Administrator account
-	if strings.HasPrefix(sid, "S-1-5-21-") && strings.HasSuffix(sid, "-500") {
-		return true
-	}
-
-	// Check for other well-known privileged RIDs in domain contexts
-	// RID 512 = Domain Admins group, RID 516 = Domain Controllers group
-	if strings.HasPrefix(sid, "S-1-5-21-") {
-		if strings.HasSuffix(sid, "-512") || // Domain Admins group
-			strings.HasSuffix(sid, "-516") || // Domain Controllers group
-			strings.HasSuffix(sid, "-519") { // Enterprise Admins group
-			return true
-		}
-	}
-
-	return false
+	return getWindowsAccountPrivilegedOrUnknown(username)
 }
 
 // isCurrentProcessPrivileged checks if the current process is running with elevated privileges.
 // On Unix systems, this means running as root (UID 0).
-// On Windows, this means running as Administrator or SYSTEM.
+// On Windows, this means the process token is elevated (administrators, SYSTEM).
 func isCurrentProcessPrivileged() bool {
 	if getCurrentOS() == "windows" {
-		return isWindowsElevated()
+		return getProcessElevated()
 	}
 	return getEuid() == 0
 }
-
-// isWindowsElevated checks if the current process is running with elevated privileges on Windows
-func isWindowsElevated() bool {
-	currentUser, err := getCurrentUser()
-	if err != nil {
-		log.Errorf("failed to get current user for privilege check, assuming non-privileged: %v", err)
-		return false
-	}
-
-	if isWindowsPrivilegedSID(currentUser.Uid) {
-		log.Debugf("Windows user switching supported: running as privileged SID %s", currentUser.Uid)
-		return true
-	}
-
-	if isPrivilegedUsername(currentUser.Username) {
-		log.Debugf("Windows user switching supported: running as privileged username %s", currentUser.Username)
-		return true
-	}
-
-	log.Debugf("Windows user switching not supported: not running as privileged user (current: %s)", currentUser.Uid)
-	return false
-}

client/ssh/server/user_utils_test.go

@@ -4,6 +4,7 @@ import (
 	"errors"
 	"os/user"
 	"runtime"
+	"strings"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -27,8 +28,8 @@ func setupTestDependencies(currentUser *user.User, currentUserErr error, os stri
 	originalLookupUser := lookupUser
 	originalGetCurrentOS := getCurrentOS
 	originalGetEuid := getEuid
-
-	// Reset caches to ensure clean test state
+	originalGetProcessElevated := getProcessElevated
+	originalGetWindowsAccountPrivilegedOrUnknown := getWindowsAccountPrivilegedOrUnknown
 
 	// Set test values - inject platform dependencies
 	getCurrentUser = func() (*user.User, error) {
@@ -53,16 +54,31 @@ func setupTestDependencies(currentUser *user.User, currentUserErr error, os stri
 		return euid
 	}
 
-	// Mock privilege detection based on the test user
-	getIsProcessPrivileged = func() bool {
+	// Simulate the Windows token elevation check based on the fixture user:
+	// the built-in Administrator (RID 500) and SYSTEM run elevated.
+	getProcessElevated = func() bool {
 		if currentUser == nil {
 			return false
 		}
-		// Check both username and SID for Windows systems
-		if os == "windows" && isWindowsPrivilegedSID(currentUser.Uid) {
+		return currentUser.Uid == "S-1-5-18" || strings.HasSuffix(currentUser.Uid, "-500")
+	}
+
+	// Simulate the Windows account classifier for the fixture accounts.
+	// "root" does not exist on Windows; the real classifier fails closed on
+	// unresolvable accounts, so it counts as privileged here too.
+	getWindowsAccountPrivilegedOrUnknown = func(username string) bool {
+		bare := username
+		if idx := strings.LastIndex(bare, `\`); idx != -1 {
+			bare = bare[idx+1:]
+		}
+		if idx := strings.Index(bare, "@"); idx != -1 {
+			bare = bare[:idx]
+		}
+		switch strings.ToLower(bare) {
+		case "administrator", "system", "root":
 			return true
 		}
-		return isPrivilegedUsername(currentUser.Username)
+		return false
 	}
 
 	// Return cleanup function
@@ -71,10 +87,8 @@ func setupTestDependencies(currentUser *user.User, currentUserErr error, os stri
 		lookupUser = originalLookupUser
 		getCurrentOS = originalGetCurrentOS
 		getEuid = originalGetEuid
-
-		getIsProcessPrivileged = isCurrentProcessPrivileged
-
-		// Reset caches after test
+		getProcessElevated = originalGetProcessElevated
+		getWindowsAccountPrivilegedOrUnknown = originalGetWindowsAccountPrivilegedOrUnknown
 	}
 }
 
@@ -421,6 +435,9 @@ func TestUsedFallback_MeansNoPrivilegeDropping(t *testing.T) {
 }
 
 func TestPrivilegedUsernameDetection(t *testing.T) {
+	// Windows classification is syscall-backed (SID resolution, group
+	// membership) and is covered by privileges_windows_test.go; here only the
+	// Unix logic and the platform dispatch are exercised.
 	tests := []struct {
 		name       string
 		username   string
@@ -432,25 +449,9 @@ func TestPrivilegedUsernameDetection(t *testing.T) {
 		{"unix_regular_user", "alice", "linux", false},
 		{"unix_root_capital", "Root", "linux", false}, // Case-sensitive
 
-		// Windows tests
+		// Windows dispatch to the (mocked) account classifier
 		{"windows_administrator", "Administrator", "windows", true},
-		{"windows_system", "SYSTEM", "windows", true},
-		{"windows_admin", "admin", "windows", true},
-		{"windows_admin_lowercase", "administrator", "windows", true}, // Case-insensitive
-		{"windows_domain_admin", "DOMAIN\\Administrator", "windows", true},
-		{"windows_email_admin", "admin@domain.com", "windows", true},
 		{"windows_regular_user", "alice", "windows", false},
-		{"windows_domain_user", "DOMAIN\\alice", "windows", false},
-		{"windows_localsystem", "localsystem", "windows", true},
-		{"windows_networkservice", "networkservice", "windows", true},
-		{"windows_localservice", "localservice", "windows", true},
-
-		// Computer accounts (these depend on current user context in real implementation)
-		{"windows_computer_account", "WIN2K19-C2$", "windows", false},      // Computer account by itself not privileged
-		{"windows_domain_computer", "DOMAIN\\COMPUTER$", "windows", false}, // Domain computer account
-
-		// Cross-platform
-		{"root_on_windows", "root", "windows", true}, // Root should be privileged everywhere
 	}
 
 	for _, tt := range tests {
@@ -459,50 +460,8 @@ func TestPrivilegedUsernameDetection(t *testing.T) {
 			cleanup := setupTestDependencies(nil, nil, tt.platform, 1000, nil, nil)
 			defer cleanup()
 
-			result := isPrivilegedUsername(tt.username)
-			assert.Equal(t, tt.privileged, result)
-		})
-	}
-}
-
-func TestWindowsPrivilegedSIDDetection(t *testing.T) {
-	tests := []struct {
-		name        string
-		sid         string
-		privileged  bool
-		description string
-	}{
-		// Well-known system accounts
-		{"system_account", "S-1-5-18", true, "Local System (SYSTEM)"},
-		{"local_service", "S-1-5-19", true, "Local Service"},
-		{"network_service", "S-1-5-20", true, "Network Service"},
-		{"administrators_group", "S-1-5-32-544", true, "Administrators group"},
-		{"builtin_administrator", "S-1-5-500", true, "Built-in Administrator"},
-
-		// Domain accounts
-		{"domain_administrator", "S-1-5-21-1234567890-1234567890-1234567890-500", true, "Domain Administrator (RID 500)"},
-		{"domain_admins_group", "S-1-5-21-1234567890-1234567890-1234567890-512", true, "Domain Admins group"},
-		{"domain_controllers_group", "S-1-5-21-1234567890-1234567890-1234567890-516", true, "Domain Controllers group"},
-		{"enterprise_admins_group", "S-1-5-21-1234567890-1234567890-1234567890-519", true, "Enterprise Admins group"},
-
-		// Regular users
-		{"regular_user", "S-1-5-21-1234567890-1234567890-1234567890-1001", false, "Regular domain user"},
-		{"another_regular_user", "S-1-5-21-1234567890-1234567890-1234567890-1234", false, "Another regular user"},
-		{"local_user", "S-1-5-21-1234567890-1234567890-1234567890-1000", false, "Local regular user"},
-
-		// Groups that are not privileged
-		{"domain_users", "S-1-5-21-1234567890-1234567890-1234567890-513", false, "Domain Users group"},
-		{"power_users", "S-1-5-32-547", false, "Power Users group"},
-
-		// Invalid SIDs
-		{"malformed_sid", "S-1-5-invalid", false, "Malformed SID"},
-		{"empty_sid", "", false, "Empty SID"},
-	}
-
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			result := isWindowsPrivilegedSID(tt.sid)
-			assert.Equal(t, tt.privileged, result, "Failed for %s: %s", tt.description, tt.sid)
+			result := isPrivilegedOrUnknown(tt.username)
+			assert.Equal(t, tt.privileged, result, "privilege classification for %s on %s", tt.username, tt.platform)
 		})
 	}
 }

client/ssh/server/userswitching_windows.go

@@ -91,7 +91,7 @@ func validateUsernameFormat(username string) error {
 func (s *Server) createExecutorCommand(logger *log.Entry, session ssh.Session, localUser *user.User, hasPty bool) (*exec.Cmd, func(), error) {
 	logger.Debugf("creating Windows executor command for user %s (Pty: %v)", localUser.Username, hasPty)
 
-	username, _ := s.parseUsername(localUser.Username)
+	username, _ := parseUsername(localUser.Username)
 	if err := validateUsername(username); err != nil {
 		return nil, nil, fmt.Errorf("invalid username %q: %w", username, err)
 	}
@@ -102,7 +102,7 @@ func (s *Server) createExecutorCommand(logger *log.Entry, session ssh.Session, l
 // createUserSwitchCommand creates a command with Windows user switching.
 // Returns the command and a cleanup function that must be called after starting the process.
 func (s *Server) createUserSwitchCommand(logger *log.Entry, session ssh.Session, localUser *user.User) (*exec.Cmd, func(), error) {
-	username, domain := s.parseUsername(localUser.Username)
+	username, domain := parseUsername(localUser.Username)
 
 	shell := getUserShell(localUser.Uid)
 
@@ -138,7 +138,7 @@ func (s *Server) createUserSwitchCommand(logger *log.Entry, session ssh.Session,
 }
 
 // parseUsername extracts username and domain from a Windows username
-func (s *Server) parseUsername(fullUsername string) (username, domain string) {
+func parseUsername(fullUsername string) (username, domain string) {
 	// Handle DOMAIN\username format
 	if idx := strings.LastIndex(fullUsername, `\`); idx != -1 {
 		domain = fullUsername[:idx]

client/ui/i18n/TRANSLATING.md

@@ -2,9 +2,24 @@
 
 A short brief for translating the desktop UI — for any translator, human or AI agent (*"you"* = whoever's translating).
 
-**Drive an agent with:** *"Read `i18n/TRANSLATING.md` and translate the UI to Russian"* — or *"…and review the existing German translation."*
+**Translations are managed on Crowdin: <https://crowdin.com/project/netbird>.** Join the project, pick your language, and translate in the editor. Each string carries a context note (the `description` from the source file) telling you what it is and where it shows up, and the project's glossary, style guide, and QA checks mirror this document.
 
-> 💡 **The one habit that matters most:** read each key's `description` before translating it. Labels are terse and ambiguous on their own; the `description` tells you what the string is, where it shows up, what to keep verbatim, and what it actually means.
+> 💡 **The one habit that matters most:** read each string's context before translating it. Labels are terse and ambiguous on their own; the context tells you what the string is, where it shows up, what to keep verbatim, and what it actually means.
+
+---
+
+## How contributions flow
+
+```text
+i18n/locales/en/common.json ──sync──▶ Crowdin ──service PR──▶ i18n/locales/<code>/common.json
+```
+
+- `i18n/locales/en/common.json` is the source of truth. New and changed strings sync to Crowdin automatically (see `crowdin.yml` in the repository root).
+- Crowdin opens and updates a service pull request with the translated bundles, keeping the source's file shape and key order. Keys nobody has translated yet are left out of the export; the app falls back to English for them at runtime. Maintainers review and merge that PR.
+- Don't hand-edit `i18n/locales/<code>/common.json` in your own PRs: the next sync would conflict with or overwrite your changes. Translate on Crowdin instead.
+- Missing your language? Request it on the Crowdin project page or in a [GitHub discussion](https://github.com/netbirdio/netbird/discussions). When a language first ships, a maintainer adds its row to `i18n/locales/_index.json` with `code`, `displayName` (the native name), and `englishName`, which puts it in the app's language picker.
+
+**Prefer translating with an AI agent?** That still works: drive it with *"Read `i18n/TRANSLATING.md` and translate the UI to Russian"* as before, but deliver the result to Crowdin instead of a pull request. Download your language's file from the Crowdin editor, let the agent translate it, and upload it back (the editor's offline translation flow). Crowdin runs its QA checks on upload, and the next service PR carries the strings into the repo.
 
 ---
 
@@ -30,25 +45,6 @@ A **business zero-trust VPN** — an encrypted **overlay mesh** between a compan
 
 ---
 
-## The files
-
-```
-i18n/locales/_index.json         shipped-language list
-i18n/locales/en/common.json      source of truth — message + description
-i18n/locales/<code>/common.json  a target — message only
-```
-
-Chrome-extension JSON, each key → `{ "message", "description" }`. You translate the **`message`**.
-
-| ✅ Do | ❌ Don't |
-|---|---|
-| Keep **every key** from `en`, in the same order | Translate, rename, reorder, drop, or add keys (they're identifiers; the set grows over time) |
-| Put **only `message`** in target bundles | Copy `description` into a target bundle |
-| Give every key a non-empty `message` | Leave keys missing or empty |
-| Save valid UTF-8 JSON, no BOM | Add trailing commas or break the JSON |
-
----
-
 ## Hard rules — get these exactly right
 
 These are the usual ways a translation *breaks the app*, not just reads oddly.
@@ -58,7 +54,7 @@ These are the usual ways a translation *breaks the app*, not just reads oddly.
 | Copy `{placeholders}` verbatim — `{version}`, `{count}`, `{name}`… | Translate the word inside the braces (`{verbleibend}` breaks it) |
 | Reposition a placeholder so the sentence flows | Drop or duplicate a placeholder |
 | Preserve every `\n`, leading/trailing space, and trailing `...` | Trim "invisible" spaces or the `...` (they're load-bearing) |
-| Keep `®` in WireGuard® and quotes around `{name}` | Strip punctuation the description flags |
+| Keep `®` in WireGuard® and quotes around `{name}` | Strip punctuation the context flags |
 
 **Plurals:** the app has only a *one / other* split — the singular key fires only when `count == 1`; the `{count}` key covers everything else (0, 2, 5, 100…). Languages with more than two forms (ru, pl, uk) can't be fully correct here — use the form that fits the widest range (Russian genitive plural: `минут` / `часов` / `дней`). Don't invent extra keys or cram multiple forms into one string. When no single form fits every value — a unit label after a number field, say — reach for a number-agnostic form (an abbreviation, or wording that reads the same for 1 and 100) instead of forcing a plural the *one / other* split can't supply.
 
@@ -78,13 +74,15 @@ When a brand sits beside a common noun, keep its exact spelling but join them th
 
 > **Use the word that language's IT users actually say.** Translate when a natural, common term exists; keep the English term *only* when the literal translation would be awkward or no one in that field really uses it.
 
-Apply each term **consistently** — same English term → same translation everywhere — and keep a term once you've settled it. Whether a term stays English or takes a native word is **language-dependent**: a technical loanword (e.g. *Daemon*, *Handshake*) often stays, an everyday word (e.g. *Latency*, *Public key*) usually localizes, and some (*Exit Node*, *Peer*) go either way depending on the language. Decide per term with the rule above — a foreign origin alone is no reason to keep English. **Your main reference is the existing bundles:** match how a term was already rendered for your language rather than re-deciding it.
+Apply each term **consistently** — same English term → same translation everywhere — and keep a term once you've settled it. Whether a term stays English or takes a native word is **language-dependent**: a technical loanword (e.g. *Daemon*, *Handshake*) often stays, an everyday word (e.g. *Latency*, *Public key*) usually localizes, and some (*Exit Node*, *Peer*) go either way depending on the language. Decide per term with the rule above — a foreign origin alone is no reason to keep English. **Your main reference is the existing translation:** match how a term was already rendered for your language rather than re-deciding it.
 
 Two checks before you commit a term:
 
 - **Prefer established localized wording.** If a widely used tool in this space (for example WireGuard) ships your language, its wording for a shared term such as *handshake* is what users already expect — look at the translated app, not just English docs. For generic UI verbs and formal address, follow your OS vendor's style guide (Microsoft / Apple / Google).
 - **Watch for false friends.** A literal translation can collide with a *different* established term in your field — confirm your word doesn't already mean something else in this domain before using it.
 
+These tiers are mirrored in the Crowdin project glossary, so the editor highlights them inline. When you settle a new Tier C term for your language, add its translation to the glossary entry so it sticks for everyone who comes after you.
+
 ---
 
 ## Style
@@ -98,7 +96,7 @@ Two checks before you commit a term:
 
 Where it reads naturally, aim to keep each string **roughly the same length** as the English — the UI is tight and over-long strings can wrap or truncate. It's a soft preference, not a rule: if your language simply needs more words, use them.
 
-A few habits that keep a bundle reading like one product rather than a word-for-word port:
+A few habits that keep a translation reading like one product rather than a word-for-word port:
 
 - **Translate meaning, not words.** Render what a string *does*. An idiom or an awkward source phrase should become natural in your language, not a literal calque.
 - **Keep one voice within a family.** Sibling strings — the connection states, every settings *help* caption, every "… Failed" title — should share a grammatical form. If one member sounds wrong in that form, re-voice the whole family rather than leave one odd sibling.
@@ -107,27 +105,26 @@ A few habits that keep a bundle reading like one product rather than a word-for-
 
 ---
 
-## Procedure
+## Reviewing a language
 
-**New language** — read `en/common.json` *with* descriptions → settle your Tier C terms → write `i18n/locales/<code>/common.json` (same keys and order as `en`, `message` only, placeholders & brands preserved) → add a row to `_index.json` (`{"code","displayName"` = native name`,"englishName"}`) → run the QA list. Use the locale-code style the existing entries use (e.g. `fr`, `pt`, `zh-CN`).
+**On Crowdin:** proofread in the editor — context, glossary highlights, and QA flags sit inline next to each string.
 
-**Review (de / hu / …)** — read source and target side by side; for each key check glossary conformance (e.g. de `Exit-Node` → `Exit Node`, hu `Kilépő csomópont` → `Exit Node`), placeholder/`\n` integrity, consistency, tone, and that the meaning matches the English `description`. Fix in place, then report what you changed (especially term standardizations) so a native speaker can sanity-check.
+**In the repo** — e.g. driving an AI agent with *"Read `i18n/TRANSLATING.md` and review the existing German translation"* — read source and target side by side; for each key check glossary conformance (e.g. de `Exit-Node` → `Exit Node`, hu `Kilépő csomópont` → `Exit Node`), placeholder/`\n` integrity, consistency, tone, and that the meaning matches the English `description`. Report what you found, and apply the fixes **on Crowdin** — direct edits to the locale files are overwritten by the next sync.
 
 ---
 
 ## QA before you finish
 
-- [ ] Valid JSON · **every `en` key** present, same order · **no `description`** fields
 - [ ] Every `{placeholder}`, `\n`, and intentional space preserved · `...` / `… Failed` / `{name}` quotes kept
-- [ ] Tier A/B left intact · Tier C applied consistently (and matching the existing bundle for your language)
+- [ ] Tier A/B left intact · Tier C applied consistently (and matching the existing translation for your language)
 - [ ] Buttons & tray short · locale punctuation and capitalization applied
-- [ ] New language added to `_index.json`
+- [ ] Crowdin QA flags resolved (variables, glossary terms, punctuation)
 - [ ] **Tested in the running app** ↓
 
 ---
 
 ## Test it in the app
 
-A bundle can pass every check above and still read wrong on screen. **Run the app, switch to your language, and click through the real surfaces** — tray menu, main window, every Settings tab, the dialogs. Watch for text overflow or truncation, labels that are technically right but wrong *for what the control does*, leaked placeholders, and terms that drift between screens.
+A translation can pass every check above and still read wrong on screen. **Run the app, switch to your language, and click through the real surfaces** — tray menu, main window, every Settings tab, the dialogs. Watch for text overflow or truncation, labels that are technically right but wrong *for what the control does*, leaked placeholders, and terms that drift between screens.
 
 How to run the app and switch language: see the project README. Can't run it (e.g. a headless agent)? Say so in your summary — don't silently skip this step.

crowdin.yml

@@ -1,8 +1,11 @@
+skip_untranslated_strings: true
+skip_untranslated_files: true
+import_eq_suggestions: true
+
 files:
   - source: /client/ui/i18n/locales/en/common.json
-    translation: /client/ui/i18n/locales/%locale%/common.json
+    translation: /client/ui/i18n/locales/%two_letters_code%/common.json
     type: chrome
     languages_mapping:
-      locale:
-        es-ES: es
-        pt-BR: pt
+      two_letters_code:
+        zh-CN: zh-CN