fix(agent): diagnostics paths collect exactly the folder the guard validated, and never the hard-blocked event logs

A configured diagnostics entry is resolved once to folder, pattern and recursion, and that target is what gets validated and enumerated; recursion asks the guard before entering a subfolder, and the user-profile token is expanded before validation. Security, PowerShell and Sysmon event logs are refused per file, by name and by resolved channel, in every mode; the portal flags such a path before it is saved. Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
2026-10-24 20:53:06 +00:00 · 2026-09-21 14:58:03 +02:00
parent 12315b2f2d
commit cb9b3fe404
11 changed files with 835 additions and 81 deletions
@@ -0,0 +1,193 @@
+using System;
+using AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather;
+using Xunit;
+
+namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.Gather
+{
+    /// <summary>
+    /// A configured diagnostics entry is resolved to the folder and pattern that get
+    /// enumerated, and the guard judges exactly that folder. The cases below pin the
+    /// property that matters: no spelling of an allowed entry ever selects its parent.
+    /// </summary>
+    public sealed class DiagnosticsPathGuardsTests
+    {
+        private const string TestProfile = @"C:\Users\TestUser";
+
+        private static readonly Func<string, bool> IsDirectory = _ => true;
+        private static readonly Func<string, bool> IsNotDirectory = _ => false;
+
+        private static DiagnosticsPathGuards.CollectionTarget Resolve(
+            string path,
+            bool includeSubfolders = false,
+            bool unrestrictedMode = false,
+            string? userProfilePath = null,
+            Func<string, bool>? directoryExists = null)
+        {
+            Assert.True(DiagnosticsPathGuards.TryResolveCollectionTarget(
+                path, includeSubfolders, unrestrictedMode, userProfilePath!, directoryExists ?? IsDirectory, out var target));
+            return target;
+        }
+
+        private static void AssertRefused(
+            string path,
+            bool unrestrictedMode = false,
+            string? userProfilePath = null,
+            Func<string, bool>? directoryExists = null)
+        {
+            Assert.False(DiagnosticsPathGuards.TryResolveCollectionTarget(
+                path, true, unrestrictedMode, userProfilePath!, directoryExists ?? IsDirectory, out var target));
+            Assert.Null(target);
+        }
+
+        // ------------------------------------------------------------ folder entries
+
+        [Theory]
+        [InlineData(@"C:\Windows\Logs")]
+        [InlineData(@"C:\Windows\Logs\")]
+        [InlineData(@"C:\Windows\SetupDiag")]
+        [InlineData(@"C:\ProgramData\AutopilotMonitor")]
+        [InlineData(@"C:\ProgramData\Microsoft\DiagnosticLogCSP")]
+        public void Folder_entry_collects_from_itself_never_from_its_parent(string configured)
+        {
+            var target = Resolve(configured, includeSubfolders: true);
+
+            Assert.Equal(configured.TrimEnd('\\'), target.Folder, ignoreCase: true);
+            Assert.Equal("*", target.Pattern);
+            Assert.True(target.Recurse);
+        }
+
+        [Fact]
+        public void Trailing_separator_means_folder_even_when_the_folder_does_not_exist_yet()
+        {
+            var target = Resolve(@"C:\Windows\Logs\NotThereYet\", directoryExists: IsNotDirectory);
+
+            Assert.Equal(@"C:\Windows\Logs\NotThereYet", target.Folder, ignoreCase: true);
+            Assert.Equal("*", target.Pattern);
+        }
+
+        [Fact]
+        public void Folder_name_with_a_dot_is_still_a_folder()
+        {
+            var target = Resolve(@"C:\Windows\Logs\vendor.v2");
+
+            Assert.Equal(@"C:\Windows\Logs\vendor.v2", target.Folder, ignoreCase: true);
+            Assert.Equal("*", target.Pattern);
+        }
+
+        // ------------------------------------------------------------ wildcard entries
+
+        [Fact]
+        public void Wildcard_entry_collects_the_pattern_from_its_validated_parent()
+        {
+            var target = Resolve(@"C:\Windows\Panther\*.log", includeSubfolders: true);
+
+            Assert.Equal(@"C:\Windows\Panther", target.Folder, ignoreCase: true);
+            Assert.Equal("*.log", target.Pattern);
+            Assert.True(target.Recurse);
+        }
+
+        [Fact]
+        public void Wildcard_beside_an_allowlisted_file_is_refused()
+        {
+            // Only ReportingEvents.log is on the allowlist, not the folder it lives in.
+            AssertRefused(@"C:\Windows\SoftwareDistribution\*.log");
+        }
+
+        // ------------------------------------------------------------ file entries
+
+        [Fact]
+        public void File_entry_never_recurses_because_its_folder_was_not_validated()
+        {
+            var target = Resolve(
+                @"C:\Windows\SoftwareDistribution\ReportingEvents.log",
+                includeSubfolders: true,
+                directoryExists: IsNotDirectory);
+
+            Assert.Equal(@"C:\Windows\SoftwareDistribution", target.Folder, ignoreCase: true);
+            Assert.Equal("ReportingEvents.log", target.Pattern);
+            Assert.False(target.Recurse);
+        }
+
+        [Fact]
+        public void Missing_path_without_a_dot_is_one_file_name_not_a_wildcard_on_the_parent()
+        {
+            var target = Resolve(@"C:\Windows\Logs\nodot", includeSubfolders: true, directoryExists: IsNotDirectory);
+
+            Assert.Equal(@"C:\Windows\Logs", target.Folder, ignoreCase: true);
+            Assert.Equal("nodot", target.Pattern);
+            Assert.False(target.Recurse);
+        }
+
+        // ------------------------------------------------------------ refusals
+
+        [Theory]
+        [InlineData(@"C:\Windows")]
+        [InlineData(@"C:\ProgramData")]
+        [InlineData(@"C:\ProgramData\Microsoft")]
+        [InlineData(@"C:\Windows\Logs\..\System32")]
+        [InlineData(@"C:\Windows\LogsEvil")]
+        [InlineData("")]
+        public void Paths_outside_the_allowlist_are_refused(string configured)
+        {
+            AssertRefused(configured);
+        }
+
+        [Theory]
+        [InlineData(@"C:\Users")]
+        [InlineData(@"C:\Users\TestUser\Documents")]
+        [InlineData(@"C:\Windows\System32\config")]
+        [InlineData(@"C:\Windows\System32\config\*")]
+        public void Hard_blocks_hold_in_unrestricted_mode(string configured)
+        {
+            AssertRefused(configured, unrestrictedMode: true);
+        }
+
+        // ------------------------------------------------------------ user-profile token
+
+        [Fact]
+        public void Expanded_token_path_outside_AppData_is_refused_even_in_unrestricted_mode()
+        {
+            // The service expands %LOGGED_ON_USER_PROFILE% before the guard sees the path; an
+            // unexpanded token is not under C:\Users lexically and used to slip past the block.
+            AssertRefused(TestProfile + @"\Documents", unrestrictedMode: true, userProfilePath: TestProfile);
+            AssertRefused(TestProfile + @"\Documents\*.txt", unrestrictedMode: true, userProfilePath: TestProfile);
+        }
+
+        [Fact]
+        public void Expanded_token_path_on_the_profile_allowlist_is_admitted_in_restricted_mode()
+        {
+            var target = Resolve(
+                TestProfile + @"\AppData\Local\RealmJoin\Logs\*.log",
+                userProfilePath: TestProfile);
+
+            Assert.Equal(TestProfile + @"\AppData\Local\RealmJoin\Logs", target.Folder, ignoreCase: true);
+            Assert.Equal("*.log", target.Pattern);
+        }
+
+        [Fact]
+        public void Profile_path_without_the_token_stays_blocked()
+        {
+            AssertRefused(TestProfile + @"\AppData\Local\RealmJoin\Logs\*.log", userProfilePath: null);
+        }
+
+        // ------------------------------------------------------------ recursion guard
+
+        [Theory]
+        [InlineData(@"C:\Users")]
+        [InlineData(@"C:\Users\TestUser")]
+        [InlineData(@"C:\Windows\System32\config")]
+        [InlineData(@"C:\Windows\System32\config\RegBack")]
+        public void Recursion_never_enters_a_hard_blocked_subtree_in_unrestricted_mode(string directory)
+        {
+            Assert.False(DiagnosticsPathGuards.IsDirectoryEnterable(directory, unrestrictedMode: true, userProfilePath: null));
+        }
+
+        [Fact]
+        public void Recursion_enters_ordinary_subfolders()
+        {
+            Assert.True(DiagnosticsPathGuards.IsDirectoryEnterable(@"C:\Windows\System32\drivers", unrestrictedMode: true, userProfilePath: null));
+            Assert.True(DiagnosticsPathGuards.IsDirectoryEnterable(@"C:\Windows\Logs\CBS", unrestrictedMode: false, userProfilePath: null));
+            Assert.False(DiagnosticsPathGuards.IsDirectoryEnterable(@"C:\Windows\System32\drivers", unrestrictedMode: false, userProfilePath: null));
+        }
+    }
+}
@@ -0,0 +1,204 @@
+#nullable enable
+using System.Collections.Generic;
+using System.IO;
+using System.IO.Compression;
+using System.Linq;
+using AutopilotMonitor.Agent.V2.Core.Configuration;
+using AutopilotMonitor.Agent.V2.Core.Logging;
+using AutopilotMonitor.Agent.V2.Core.Monitoring.Runtime;
+using AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather;
+using AutopilotMonitor.Agent.V2.Core.Monitoring.Transport;
+using AutopilotMonitor.Agent.V2.Core.Tests.Harness;
+using AutopilotMonitor.Shared.Models;
+using Xunit;
+
+namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.Runtime
+{
+    /// <summary>
+    /// The hard-blocked event-log channels (Security, PowerShell, Sysmon) are unreadable through
+    /// the diagnostics package as well — by path, by wildcard, by resolved channel, and in
+    /// unrestricted mode. Before this the block held only in the event-log collector.
+    /// </summary>
+    public sealed class DiagnosticsEventLogBlockTests
+    {
+        private const string WinevtLogs = @"C:\Windows\System32\winevt\Logs";
+
+        // A channel no machine has: the export fails and the packager falls back to the raw copy.
+        private const string HarmlessChannel = "AutopilotMonitor-Tests-NoSuchChannel/Operational";
+
+        [Theory]
+        [InlineData("Security.evtx")]
+        [InlineData("security.EVTX")]
+        [InlineData("Microsoft-Windows-PowerShell%4Operational.evtx")]
+        [InlineData("Microsoft-Windows-PowerShell%4Admin.evtx")]
+        [InlineData("Windows PowerShell.evtx")]
+        [InlineData("Microsoft-Windows-Sysmon%4Operational.evtx")]
+        [InlineData("Archive-Security-2026-09-21-10-15-30-123.evtx")]
+        [InlineData("Archive-Microsoft-Windows-PowerShell%4Operational-2026-09-21-10-15-30-123.evtx")]
+        public void Hard_blocked_channel_files_are_recognised_by_name(string fileName)
+        {
+            Assert.True(DiagnosticsPathGuards.IsHardBlockedEventLogFile(Path.Combine(WinevtLogs, fileName)));
+        }
+
+        [Theory]
+        [InlineData("System.evtx")]
+        [InlineData("Application.evtx")]
+        [InlineData("SecurityAudit.evtx")]
+        [InlineData("Security.log")]
+        [InlineData("Microsoft-Windows-Security-Mitigations%4KernelMode.evtx")]
+        // Same boundary as the collector: only '/' continues a blocked channel name.
+        [InlineData("Microsoft-Windows-PowerShell-DesiredStateConfiguration-FileDownloadManager%4Operational.evtx")]
+        [InlineData("Archive-System-2026-09-21-10-15-30-123.evtx")]
+        public void Other_files_are_not_mistaken_for_a_blocked_channel(string fileName)
+        {
+            Assert.False(DiagnosticsPathGuards.IsHardBlockedEventLogFile(Path.Combine(WinevtLogs, fileName)));
+        }
+
+        [Theory]
+        [InlineData(false)]
+        [InlineData(true)]
+        public void Path_guard_refuses_a_blocked_channel_file_in_every_mode(bool unrestrictedMode)
+        {
+            Assert.False(DiagnosticsPathGuards.IsDiagnosticsPathAllowed(
+                WinevtLogs + @"\Security.evtx", unrestrictedMode));
+            Assert.False(DiagnosticsPathGuards.IsDiagnosticsPathAllowed(
+                WinevtLogs + @"\Microsoft-Windows-PowerShell%4Operational.evtx", unrestrictedMode));
+        }
+
+        [Fact]
+        public void Path_guard_still_admits_other_channels_and_wildcards()
+        {
+            Assert.True(DiagnosticsPathGuards.IsDiagnosticsPathAllowed(WinevtLogs + @"\System.evtx"));
+            // Undecidable on the string — the packager filters per file (tests below).
+            Assert.True(DiagnosticsPathGuards.IsDiagnosticsPathAllowed(WinevtLogs + @"\*.evtx"));
+        }
+
+        [Theory]
+        [InlineData("Security", true)]
+        [InlineData("Microsoft-Windows-PowerShell/Operational", true)]
+        [InlineData(" Windows PowerShell ", true)]
+        [InlineData("Microsoft-Windows-Sysmon/Operational", true)]
+        [InlineData("System", false)]
+        [InlineData("", false)]
+        [InlineData(null, false)]
+        public void Channel_block_is_one_matcher_for_collector_and_package(string? channel, bool blocked)
+        {
+            Assert.Equal(blocked, GatherRuleGuards.IsHardBlockedEventLogChannel(channel!));
+        }
+
+        // ------------------------------------------------------------ packager ----
+
+        // %TEMP% lives under C:\Users, which the path guard blocks in every mode, so the
+        // configured folder sits beside the test assembly and the run is unrestricted — which
+        // is also the strongest form of the claim: not even unrestricted mode collects these.
+        private sealed class EvtxFolder : System.IDisposable
+        {
+            public string Path { get; } = System.IO.Path.Combine(
+                System.AppContext.BaseDirectory, "diag-evtx-" + System.Guid.NewGuid().ToString("N"));
+
+            public EvtxFolder(params string[] fileNames)
+            {
+                Directory.CreateDirectory(Path);
+                foreach (var name in fileNames)
+                    File.WriteAllBytes(System.IO.Path.Combine(Path, name), new byte[] { 1, 2, 3 });
+            }
+
+            public void Dispose()
+            {
+                try { Directory.Delete(Path, recursive: true); } catch { }
+            }
+        }
+
+        private static DiagnosticsPackageService BuildService(
+            TempDirectory scratch, string configuredPath, System.Func<string, string> channelResolver)
+        {
+            var logger = new AgentLogger(Directory.CreateDirectory(Path.Combine(scratch.Path, "logs")).FullName);
+            var apiClient = new BackendApiClient(
+                httpClient: new System.Net.Http.HttpClient(),
+                baseUrl: "http://localhost",
+                manufacturer: string.Empty,
+                model: string.Empty,
+                serialNumber: string.Empty,
+                useBootstrapTokenAuth: false,
+                bootstrapToken: null,
+                agentVersion: "0.0.0",
+                logger: logger);
+
+            var cfg = new AgentConfiguration
+            {
+                SessionId = "S1",
+                TenantId = "T1",
+                ApiBaseUrl = "http://localhost",
+                UnrestrictedMode = true,
+            };
+            cfg.DiagnosticsLogPaths.Add(new DiagnosticsLogPath { Path = configuredPath });
+
+            string Sub(string name) => Directory.CreateDirectory(Path.Combine(scratch.Path, name)).FullName;
+            return new DiagnosticsPackageService(
+                cfg,
+                logger,
+                apiClient,
+                agentLogFolderOverride: Sub("agentlogs"),
+                imeLogFolderOverride: Sub("ime"),
+                agentStateFolderOverride: Sub("state"),
+                agentSpoolFolderOverride: Sub("spool"),
+                agentDataFolderOverride: Sub("data"),
+                sectionFolderOverrides: null,
+                devicePreparationProbe: () => false)
+            {
+                EventLogChannelResolver = channelResolver,
+            };
+        }
+
+        private static List<string> ZipEntryNames(byte[] bytes)
+        {
+            using var ms = new MemoryStream(bytes);
+            using var archive = new ZipArchive(ms, ZipArchiveMode.Read);
+            return archive.Entries.Select(e => e.FullName).ToList();
+        }
+
+        private static string ReadManifest(byte[] bytes)
+        {
+            using var ms = new MemoryStream(bytes);
+            using var archive = new ZipArchive(ms, ZipArchiveMode.Read);
+            using var reader = new StreamReader(archive.GetEntry("package-manifest.txt")!.Open());
+            return reader.ReadToEnd();
+        }
+
+        [Fact]
+        public void Wildcard_entry_skips_blocked_channel_files_and_keeps_the_rest()
+        {
+            using var scratch = new TempDirectory();
+            using var folder = new EvtxFolder(
+                "Security.evtx", "Microsoft-Windows-PowerShell%4Operational.evtx", "Setup.evtx");
+
+            var service = BuildService(scratch, Path.Combine(folder.Path, "*.evtx"), _ => HarmlessChannel);
+            var bytes = service.BuildArchiveBytes(enrollmentSucceeded: false);
+
+            var entries = ZipEntryNames(bytes);
+            Assert.Contains(entries, e => e.EndsWith("/Setup.evtx"));
+            Assert.DoesNotContain(entries, e => e.EndsWith("Security.evtx"));
+            Assert.DoesNotContain(entries, e => e.Contains("PowerShell"));
+
+            var manifest = ReadManifest(bytes);
+            Assert.Contains("BLOCKED (event-log channel guard", manifest);
+            Assert.Contains("Security.evtx", manifest);
+            Assert.Equal(2, service.LastPackaging!.ProblemsByKind["path-guard"]);
+        }
+
+        [Fact]
+        public void File_with_a_harmless_name_is_blocked_when_it_resolves_to_a_blocked_channel()
+        {
+            // A channel is free to write to any file name; and the resolver's naming fallback
+            // maps a stray file onto a live channel. The export must never read that channel.
+            using var scratch = new TempDirectory();
+            using var folder = new EvtxFolder("Harmless.evtx");
+
+            var service = BuildService(scratch, Path.Combine(folder.Path, "Harmless.evtx"), _ => "Security");
+            var bytes = service.BuildArchiveBytes(enrollmentSucceeded: false);
+
+            Assert.DoesNotContain(ZipEntryNames(bytes), e => e.EndsWith("Harmless.evtx"));
+            Assert.Contains("BLOCKED (event-log channel guard, channel 'Security')", ReadManifest(bytes));
+        }
+    }
+}
@@ -206,6 +206,91 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.Runtime
            Assert.Contains($"BLOCKED (path guard): {configuredPath}", manifest);
        }

+        // %TEMP% lives under C:\Users, which the guard blocks in every mode — the positive
+        // configured-path cases run beside the test assembly, in unrestricted mode.
+        private sealed class ConfiguredPathTree : System.IDisposable
+        {
+            public string Root { get; } = Path.Combine(
+                System.AppContext.BaseDirectory, "diag-paths-" + System.Guid.NewGuid().ToString("N"));
+            public string Logs => Path.Combine(Root, "Logs");
+
+            public ConfiguredPathTree()
+            {
+                Directory.CreateDirectory(Path.Combine(Logs, "sub"));
+                File.WriteAllText(Path.Combine(Root, "parent-only.txt"), "not configured");
+                File.WriteAllText(Path.Combine(Logs, "app.log"), "configured");
+                File.WriteAllText(Path.Combine(Logs, "sub", "app.log"), "below");
+            }
+
+            public void Dispose()
+            {
+                try { Directory.Delete(Root, recursive: true); } catch { /* best effort */ }
+            }
+        }
+
+        [Theory]
+        [InlineData("")]
+        [InlineData("\\")]
+        public void BuildArchiveBytes_folder_entry_collects_the_folder_not_its_parent(string trailing)
+        {
+            using var rig = new Rig();
+            using var tree = new ConfiguredPathTree();
+
+            var bytes = rig.Build(cfg =>
+                {
+                    cfg.UnrestrictedMode = true;
+                    cfg.DiagnosticsLogPaths.Add(new AutopilotMonitor.Shared.Models.DiagnosticsLogPath
+                    {
+                        Path = tree.Logs + trailing,
+                        IncludeSubfolders = true,
+                    });
+                })
+                .BuildArchiveBytes(enrollmentSucceeded: true);
+
+            var entries = ZipEntryNames(bytes);
+            Assert.Contains("AdditionalLogs/Logs/app.log", entries);
+            Assert.Contains("AdditionalLogs/Logs/sub/app.log", entries);
+            Assert.DoesNotContain(entries, e => e.EndsWith("parent-only.txt"));
+        }
+
+        [Fact]
+        public void BuildArchiveBytes_file_entry_ignores_include_subfolders()
+        {
+            using var rig = new Rig();
+            using var tree = new ConfiguredPathTree();
+
+            var bytes = rig.Build(cfg =>
+                {
+                    cfg.UnrestrictedMode = true;
+                    cfg.DiagnosticsLogPaths.Add(new AutopilotMonitor.Shared.Models.DiagnosticsLogPath
+                    {
+                        Path = Path.Combine(tree.Logs, "app.log"),
+                        IncludeSubfolders = true,
+                    });
+                })
+                .BuildArchiveBytes(enrollmentSucceeded: true);
+
+            var entries = ZipEntryNames(bytes);
+            Assert.Contains("AdditionalLogs/Logs/app.log", entries);
+            Assert.DoesNotContain("AdditionalLogs/Logs/sub/app.log", entries);
+        }
+
+        [Fact]
+        public void EnumerateFilesNoReparseDirs_asks_the_guard_before_entering_a_subfolder()
+        {
+            using var tree = new ConfiguredPathTree();
+            var refused = new List<string>();
+
+            var files = DiagnosticsPackageService.EnumerateFilesNoReparseDirs(
+                tree.Root, "*", recurse: true,
+                mayEnterDirectory: dir => !dir.EndsWith("sub"),
+                refusedDirectories: refused);
+
+            Assert.Contains(Path.Combine(tree.Logs, "app.log"), files);
+            Assert.DoesNotContain(Path.Combine(tree.Logs, "sub", "app.log"), files);
+            Assert.Equal(new[] { Path.Combine(tree.Logs, "sub") }, refused);
+        }
+
        [Fact]
        public void BuildArchiveBytes_excludes_top_level_session_id_and_bootstrap_config()
        {
@@ -99,7 +99,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Runtime

        /// <summary>
        /// Packaging problems that are not cap skips, per kind: <c>path-guard</c> (configured path
-        /// refused), <c>no-user-session</c> (user-profile token without a signed-in user),
+        /// or hard-blocked event log refused),<c>no-user-session</c> (user-profile token without a signed-in user),
        /// <c>folder-rejected</c>, <c>enumerate</c>, <c>open</c>, <c>copy</c>.
        /// </summary>
        public IReadOnlyDictionary<string, int> ProblemsByKind { get; set; } = Empty;
@@ -145,6 +145,10 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Runtime
        // exact point production is exposed. Null in production.
        internal Action<string> BeforeSourceFileOpen { get; set; }

+        // Test seam: which channel writes to an .evtx file. Production asks the registered
+        // channels; a test cannot register one.
+        internal Func<string, string> EventLogChannelResolver { get; set; } = ResolveChannelForEvtxFile;
+
        // Tracks per-build inclusion totals + skip reasons. Threaded through every
        // AddLogFiles call so caps are global across all sections, not per section.
        private sealed class BudgetTracker
@@ -462,17 +466,12 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Runtime
                    // 3. Configured additional log paths (global + tenant, validated by guards)
                    foreach (var entry in _configuration.DiagnosticsLogPaths ?? new System.Collections.Generic.List<Shared.Models.DiagnosticsLogPath>())
                    {
-                        // Resolve %LOGGED_ON_USER_PROFILE% token and get profile path for guard exception
+                        // The profile path only lifts the C:\Users block for entries that use the token.
                        var userProfilePath = UserProfileResolver.ContainsUserProfileToken(entry.Path)
                            ? UserProfileResolver.GetLoggedOnUserProfilePath() : null;

-                        if (!DiagnosticsPathGuards.IsDiagnosticsPathAllowed(entry.Path, _configuration.UnrestrictedMode, userProfilePath))
-                        {
-                            _logger.Warning($"Diagnostics path blocked by guard: {entry.Path}");
-                            ManifestLine($"BLOCKED (path guard): {entry.Path}");
-                            tracker.RecordProblem("path-guard");
-                            continue;
-                        }
+                        // Expand BEFORE the guard: the guard must judge the path that is read,
+                        // and an unresolved token is not a path it can judge.
                        var expandedPath = UserProfileResolver.ExpandCustomTokens(entry.Path);
                        if (expandedPath == null)
                        {
@@ -481,13 +480,23 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Runtime
                            tracker.RecordProblem("no-user-session");
                            continue;
                        }
-                        var folder = Path.GetDirectoryName(expandedPath);
-                        var pattern = Path.GetFileName(expandedPath);
-                        if (string.IsNullOrEmpty(folder)) continue;
-                        if (string.IsNullOrEmpty(pattern) || !pattern.Contains(".")) pattern = "*";
-                        var zipFolder = $"AdditionalLogs/{Path.GetFileName(folder)}";
-                        ManifestLine($"CONFIGURED PATH: '{entry.Path}' -> folder='{folder}' pattern='{pattern}'");
-                        AddLogFiles(archive, folder, zipFolder, pattern, tracker, entry.IncludeSubfolders);
+
+                        // The guard validates the folder that gets enumerated — never a path
+                        // derived from the validated one afterwards.
+                        if (!DiagnosticsPathGuards.TryResolveCollectionTarget(
+                                expandedPath, entry.IncludeSubfolders, _configuration.UnrestrictedMode, userProfilePath, out var target))
+                        {
+                            _logger.Warning($"Diagnostics path blocked by guard: {entry.Path}");
+                            ManifestLine($"BLOCKED (path guard): {entry.Path}");
+                            tracker.RecordProblem("path-guard");
+                            continue;
+                        }
+
+                        var unrestrictedMode = _configuration.UnrestrictedMode;
+                        var zipFolder = $"AdditionalLogs/{Path.GetFileName(target.Folder)}";
+                        ManifestLine($"CONFIGURED PATH: '{entry.Path}' -> folder='{target.Folder}' pattern='{target.Pattern}' recursive={target.Recurse}");
+                        AddLogFiles(archive, target.Folder, zipFolder, target.Pattern, tracker, target.Recurse,
+                            dir => DiagnosticsPathGuards.IsDirectoryEnterable(dir, unrestrictedMode, userProfilePath));
                    }

                    // Packaging manifest — always written, even when empty of problems, so its
@@ -617,14 +626,18 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Runtime
        // Recursive enumeration that skips reparse-point directories. Materializes the
        // result into a list so the caller can iterate without holding a directory handle.
        // Errors during enumeration are swallowed (logged via _logger by the caller).
-        private static List<string> EnumerateFilesNoReparseDirs(string folder, string pattern, bool recurse)
+        // mayEnterDirectory (configured paths only) is asked for every subdirectory before the
+        // walk descends: a hard-blocked subtree can sit below a folder that passed the guard.
+        internal static List<string> EnumerateFilesNoReparseDirs(string folder, string pattern, bool recurse,
+            Func<string, bool> mayEnterDirectory, List<string> refusedDirectories)
        {
            var result = new List<string>();
-            CollectFilesNoReparseDirs(folder, pattern, recurse, result);
+            CollectFilesNoReparseDirs(folder, pattern, recurse, mayEnterDirectory, refusedDirectories, result);
            return result;
        }

-        private static void CollectFilesNoReparseDirs(string folder, string pattern, bool recurse, List<string> result)
+        private static void CollectFilesNoReparseDirs(string folder, string pattern, bool recurse,
+            Func<string, bool> mayEnterDirectory, List<string> refusedDirectories, List<string> result)
        {
            string[] files;
            try { files = Directory.GetFiles(folder, pattern, SearchOption.TopDirectoryOnly); }
@@ -643,12 +656,17 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Runtime
                try { attrs = File.GetAttributes(sub); }
                catch { continue; }
                if (IsReparsePoint(attrs)) continue;
-                CollectFilesNoReparseDirs(sub, pattern, recurse: true, result);
+                if (mayEnterDirectory != null && !mayEnterDirectory(sub))
+                {
+                    refusedDirectories.Add(sub);
+                    continue;
+                }
+                CollectFilesNoReparseDirs(sub, pattern, recurse: true, mayEnterDirectory, refusedDirectories, result);
            }
        }

        private void AddLogFiles(ZipArchive archive, string sourceFolder, string zipFolder, string searchPattern,
-            BudgetTracker tracker, bool includeSubfolders = false)
+            BudgetTracker tracker, bool includeSubfolders = false, Func<string, bool> mayEnterDirectory = null)
        {
            // The folder stays pinned (open handle) for this whole section. The path guards and
            // the enumeration below only ever judge path strings; every byte that reaches the
@@ -673,9 +691,11 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Runtime
                }

                List<string> files;
+                var refusedDirectories = new List<string>();
                try
                {
-                    files = EnumerateFilesNoReparseDirs(pinned.LexicalPath, searchPattern, includeSubfolders);
+                    files = EnumerateFilesNoReparseDirs(pinned.LexicalPath, searchPattern, includeSubfolders,
+                        mayEnterDirectory, refusedDirectories);
                }
                catch (Exception ex)
                {
@@ -685,6 +705,13 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Runtime
                    return;
                }

+                // Expected outcome, not a packaging problem: the subtree is off limits by design.
+                foreach (var refused in refusedDirectories)
+                {
+                    _logger.Info($"Diagnostics subfolder skipped by guard: {refused}");
+                    ManifestLine($"SKIPPED DIR (path guard): {refused}");
+                }
+
                if (files.Count == 0)
                    ManifestLine($"NO MATCH: {sourceFolder} pattern '{searchPattern}'");

@@ -704,7 +731,22 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Runtime
                // the tenant-configured BootstrapperAgent channel never made it into the ZIP.
                if (file.EndsWith(".evtx", StringComparison.OrdinalIgnoreCase))
                {
-                    tempExport = TryExportEventLogChannel(file);
+                    // Hard-blocked channels are refused for every source and in every mode,
+                    // by file name AND by the channel the export would read: the path guard
+                    // cannot judge what a wildcard or folder entry resolves to, and the %4
+                    // fallback of the resolver turns a "Security.evtx" in any allowed folder
+                    // into the live Security channel.
+                    var channel = EventLogChannelResolver(file);
+                    if (DiagnosticsPathGuards.IsHardBlockedEventLogFile(file) ||
+                        GatherRuleGuards.IsHardBlockedEventLogChannel(channel))
+                    {
+                        _logger.Warning($"Event log blocked by channel guard (channel '{channel}'): {file}");
+                        ManifestLine($"BLOCKED (event-log channel guard, channel '{channel}'): {file}");
+                        tracker.RecordProblem("path-guard");
+                        return;
+                    }
+
+                    tempExport = TryExportEventLogChannel(file, channel);
                    if (tempExport == null)
                    {
                        // Export failed (channel not resolvable / wevtutil error) — fall through
@@ -850,16 +892,16 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Runtime
        /// <summary>
        /// Exports the event-log channel behind a winevt .evtx file to a temp copy via
        /// <c>wevtutil epl</c> (active channels hold their file exclusively locked, so a raw
-        /// copy fails). Channel resolution happens against the registered channels — see
-        /// <see cref="ResolveChannelForEvtxFile"/>. Returns the temp file path (caller deletes)
-        /// or null when the export failed.
+        /// copy fails). The caller resolved <paramref name="channel"/> against the registered
+        /// channels — see <see cref="ResolveChannelForEvtxFile"/> — and checked it against the
+        /// hard-blocked channels. Returns the temp file path (caller deletes) or null when the
+        /// export failed.
        /// </summary>
-        private string TryExportEventLogChannel(string evtxPath)
+        private string TryExportEventLogChannel(string evtxPath, string channel)
        {
            string tempPath = null;
            try
            {
-                var channel = ResolveChannelForEvtxFile(evtxPath);
                tempPath = Path.Combine(Path.GetTempPath(), $"am-evtx-{Guid.NewGuid():N}.evtx");
                var psi = new System.Diagnostics.ProcessStartInfo
                {
@@ -2,6 +2,7 @@ using System;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
+using System.Text.RegularExpressions;

 namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather
 {
@@ -124,51 +125,7 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather
                if (IsSymlinkOrReparsePoint(normalizedDir))
                    return false;

-                // C:\Users block always applies (even in unrestricted mode)
-                // Exception: paths under <userProfilePath>\AppData\Local or AppData\Roaming
-                // are allowed when the %LOGGED_ON_USER_PROFILE% token was used.
-                if (normalizedDir.StartsWith(BlockedUsersPrefix, StringComparison.OrdinalIgnoreCase) &&
-                    (normalizedDir.Length == BlockedUsersPrefix.Length ||
-                     normalizedDir[BlockedUsersPrefix.Length] == Path.DirectorySeparatorChar))
-                {
-                    if (!GatherRuleGuards.IsUserProfileSubpathAllowed(normalizedDir, userProfilePath))
-                        return false;
-                }
-
-                // Additional hard-blocked paths (even in unrestricted mode)
-                foreach (var blocked in AdditionalHardBlockedPrefixes)
-                {
-                    var normalizedBlocked = Path.GetFullPath(blocked);
-                    if (normalizedDir.StartsWith(normalizedBlocked, StringComparison.OrdinalIgnoreCase) &&
-                        (normalizedDir.Length == normalizedBlocked.Length ||
-                         normalizedDir[normalizedBlocked.Length] == Path.DirectorySeparatorChar))
-                    {
-                        return false;
-                    }
-                }
-
-                // In unrestricted mode, everything except hard-blocked paths is allowed
-                if (unrestrictedMode)
-                    return true;
-
-                foreach (var prefix in AllowedDiagnosticsPathPrefixes)
-                {
-                    var normalizedPrefix = Path.GetFullPath(prefix);
-                    if (normalizedDir.StartsWith(normalizedPrefix, StringComparison.OrdinalIgnoreCase))
-                    {
-                        // Segment-bounded: next char must be '\' or end-of-string
-                        if (normalizedDir.Length == normalizedPrefix.Length ||
-                            normalizedDir[normalizedPrefix.Length] == Path.DirectorySeparatorChar)
-                        {
-                            return true;
-                        }
-                    }
-                }
-
-                // Vendor folders under the signed-in user's profile — same allowlist the file
-                // collectors use, since it answers the same question: which folders below a
-                // profile carry enrollment-relevant logs rather than the user's own data.
-                return GatherRuleGuards.IsUserProfilePathOnAllowlist(normalizedDir, userProfilePath);
+                return IsNormalizedPathAllowed(normalizedDir, unrestrictedMode, userProfilePath);
            }
            catch
            {
@@ -177,6 +134,213 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather
            }
        }

+        /// <summary>
+        /// What the package actually reads for one configured entry: every file matching
+        /// <see cref="Pattern"/> in <see cref="Folder"/>, optionally below it.
+        /// </summary>
+        public sealed class CollectionTarget
+        {
+            public CollectionTarget(string folder, string pattern, bool recurse)
+            {
+                Folder = folder;
+                Pattern = pattern;
+                Recurse = recurse;
+            }
+
+            /// <summary>Full path without a trailing separator (drive roots keep theirs).</summary>
+            public string Folder { get; }
+            public string Pattern { get; }
+            public bool Recurse { get; }
+        }
+
+        /// <summary>
+        /// Resolves a configured entry to the folder and pattern that get enumerated, and
+        /// validates exactly that. Returns false when the guard refuses the entry.
+        ///
+        /// <paramref name="expandedPath"/> must already have the %LOGGED_ON_USER_PROFILE% token
+        /// resolved: validating the raw token would judge a different path than the one read.
+        ///
+        /// A wildcard in the last segment selects files in its parent folder. A trailing
+        /// separator or an existing directory selects every file in that folder. Anything else
+        /// names one file — validated as that file and never recursed, because its parent
+        /// folder has not passed the guard. The filesystem decides folder-vs-file, never the
+        /// spelling of the last segment.
+        /// </summary>
+        public static bool TryResolveCollectionTarget(
+            string expandedPath,
+            bool includeSubfolders,
+            bool unrestrictedMode,
+            string userProfilePath,
+            out CollectionTarget target)
+            => TryResolveCollectionTarget(
+                expandedPath, includeSubfolders, unrestrictedMode, userProfilePath, Directory.Exists, out target);
+
+        internal static bool TryResolveCollectionTarget(
+            string expandedPath,
+            bool includeSubfolders,
+            bool unrestrictedMode,
+            string userProfilePath,
+            Func<string, bool> directoryExists,
+            out CollectionTarget target)
+        {
+            target = null;
+            if (string.IsNullOrWhiteSpace(expandedPath))
+                return false;
+
+            try
+            {
+                var expanded = Environment.ExpandEnvironmentVariables(expandedPath.Trim());
+                var lastSegment = Path.GetFileName(expanded);
+
+                if (lastSegment.Contains('*') || lastSegment.Contains('?'))
+                {
+                    var parent = Path.GetDirectoryName(expanded);
+                    if (string.IsNullOrEmpty(parent))
+                        return false;
+                    var folder = TrimTrailingSeparators(Path.GetFullPath(parent));
+                    if (!IsDiagnosticsPathAllowed(folder, unrestrictedMode, userProfilePath))
+                        return false;
+                    target = new CollectionTarget(folder, lastSegment, includeSubfolders);
+                    return true;
+                }
+
+                var full = TrimTrailingSeparators(Path.GetFullPath(expanded));
+                if (!IsDiagnosticsPathAllowed(full, unrestrictedMode, userProfilePath))
+                    return false;
+
+                if (lastSegment.Length == 0 || directoryExists(full))
+                {
+                    target = new CollectionTarget(full, "*", includeSubfolders);
+                    return true;
+                }
+
+                var fileFolder = Path.GetDirectoryName(full);
+                if (string.IsNullOrEmpty(fileFolder))
+                    return false;
+                target = new CollectionTarget(fileFolder, Path.GetFileName(full), recurse: false);
+                return true;
+            }
+            catch
+            {
+                target = null;
+                return false;
+            }
+        }
+
+        /// <summary>
+        /// Guard for every subdirectory a recursive collection is about to enter. The start
+        /// folder passed <see cref="IsDiagnosticsPathAllowed(string, bool, string)"/>, but a
+        /// hard-blocked subtree can sit below an allowed folder (unrestricted mode, drive
+        /// root). Lexical only: reparse points are skipped by the enumeration and refused
+        /// again on the handle that is read.
+        /// </summary>
+        public static bool IsDirectoryEnterable(string directory, bool unrestrictedMode, string userProfilePath)
+        {
+            if (string.IsNullOrWhiteSpace(directory))
+                return false;
+
+            try
+            {
+                return IsNormalizedPathAllowed(Path.GetFullPath(directory), unrestrictedMode, userProfilePath);
+            }
+            catch
+            {
+                return false;
+            }
+        }
+
+        private static string TrimTrailingSeparators(string fullPath)
+        {
+            var root = Path.GetPathRoot(fullPath);
+            var trimmed = fullPath.TrimEnd(Path.DirectorySeparatorChar, Path.AltDirectorySeparatorChar);
+            return root != null && trimmed.Length < root.Length ? root : trimmed;
+        }
+
+        // Hard blocks, then (restricted mode) the allowlists — on an already normalized path.
+        private static bool IsNormalizedPathAllowed(string normalizedDir, bool unrestrictedMode, string userProfilePath)
+        {
+            // C:\Users block always applies (even in unrestricted mode)
+            // Exception: paths under <userProfilePath>\AppData\Local or AppData\Roaming
+            // are allowed when the %LOGGED_ON_USER_PROFILE% token was used.
+            if (normalizedDir.StartsWith(BlockedUsersPrefix, StringComparison.OrdinalIgnoreCase) &&
+                (normalizedDir.Length == BlockedUsersPrefix.Length ||
+                 normalizedDir[BlockedUsersPrefix.Length] == Path.DirectorySeparatorChar))
+            {
+                if (!GatherRuleGuards.IsUserProfileSubpathAllowed(normalizedDir, userProfilePath))
+                    return false;
+            }
+
+            // Additional hard-blocked paths (even in unrestricted mode)
+            foreach (var blocked in AdditionalHardBlockedPrefixes)
+            {
+                var normalizedBlocked = Path.GetFullPath(blocked);
+                if (normalizedDir.StartsWith(normalizedBlocked, StringComparison.OrdinalIgnoreCase) &&
+                    (normalizedDir.Length == normalizedBlocked.Length ||
+                     normalizedDir[normalizedBlocked.Length] == Path.DirectorySeparatorChar))
+                {
+                    return false;
+                }
+            }
+
+            // Hard-blocked event logs (even in unrestricted mode). Only a path that names the
+            // file is caught here; a wildcard or folder entry is judged per file by
+            // DiagnosticsPackageService, which is the enforcement point.
+            if (IsHardBlockedEventLogFile(normalizedDir))
+                return false;
+
+            // In unrestricted mode, everything except hard-blocked paths is allowed
+            if (unrestrictedMode)
+                return true;
+
+            foreach (var prefix in AllowedDiagnosticsPathPrefixes)
+            {
+                var normalizedPrefix = Path.GetFullPath(prefix);
+                if (normalizedDir.StartsWith(normalizedPrefix, StringComparison.OrdinalIgnoreCase))
+                {
+                    // Segment-bounded: next char must be '\' or end-of-string
+                    if (normalizedDir.Length == normalizedPrefix.Length ||
+                        normalizedDir[normalizedPrefix.Length] == Path.DirectorySeparatorChar)
+                    {
+                        return true;
+                    }
+                }
+            }
+
+            // Vendor folders under the signed-in user's profile — same allowlist the file
+            // collectors use, since it answers the same question: which folders below a
+            // profile carry enrollment-relevant logs rather than the user's own data.
+            return GatherRuleGuards.IsUserProfilePathOnAllowlist(normalizedDir, userProfilePath);
+        }
+
+        // Windows archives a full channel as "Archive-<file name>-yyyy-MM-dd-HH-mm-ss-fff.evtx".
+        private static readonly Regex ArchivedEventLogRegex = new Regex(
+            @"^Archive-(.+)-\d{4}-\d{2}-\d{2}-\d{2}-\d{2}-\d{2}-\d{3}$",
+            RegexOptions.IgnoreCase | RegexOptions.CultureInvariant | RegexOptions.Compiled);
+
+        /// <summary>
+        /// True when the .evtx file name belongs to one of
+        /// <see cref="GatherRuleGuards.HardBlockedEventLogChannels"/> — live file
+        /// ("Microsoft-Windows-PowerShell%4Operational.evtx", where %4 encodes '/') or
+        /// archived copy. Judges the NAME only; a channel may write to a file that does not
+        /// follow the convention, so the packager also checks the channel it resolved.
+        /// </summary>
+        internal static bool IsHardBlockedEventLogFile(string path)
+        {
+            if (string.IsNullOrEmpty(path))
+                return false;
+
+            var name = Path.GetFileName(path);
+            if (!name.EndsWith(".evtx", StringComparison.OrdinalIgnoreCase))
+                return false;
+
+            var stem = name.Substring(0, name.Length - ".evtx".Length);
+            var archived = ArchivedEventLogRegex.Match(stem);
+            if (archived.Success)
+                stem = archived.Groups[1].Value;
+
+            return GatherRuleGuards.IsHardBlockedEventLogChannel(stem.Replace("%4", "/"));
+        }
+
        /// <summary>
        /// Checks whether any component of the path (directories or file) is a symlink,
        /// junction, or other reparse point. Returns true if a reparse point is detected.
@@ -451,11 +451,8 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather
            var trimmed = channel.Trim();

            // Hard blocks apply even in unrestricted mode
-            foreach (var blocked in HardBlockedEventLogChannels)
-            {
-                if (MatchesChannel(trimmed, blocked))
-                    return false;
-            }
+            if (IsHardBlockedEventLogChannel(trimmed))
+                return false;

            if (unrestrictedMode)
                return true;
@@ -463,6 +460,20 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Gather
            return AllowedEventLogChannels.Any(allowed => MatchesChannel(trimmed, allowed));
        }

+        /// <summary>
+        /// True when the channel is one of <see cref="HardBlockedEventLogChannels"/>. Every
+        /// path that can read an event log asks here — the event-log collector and the
+        /// diagnostics package alike — so the block cannot hold in one and leak through another.
+        /// </summary>
+        internal static bool IsHardBlockedEventLogChannel(string channel)
+        {
+            if (string.IsNullOrWhiteSpace(channel))
+                return false;
+
+            var trimmed = channel.Trim();
+            return HardBlockedEventLogChannels.Any(blocked => MatchesChannel(trimmed, blocked));
+        }
+
        private static bool MatchesChannel(string channel, string prefix)
            => channel.StartsWith(prefix, StringComparison.OrdinalIgnoreCase) &&
               (channel.Length == prefix.Length || channel[prefix.Length] == '/');
@@ -79,7 +79,7 @@ export function DiagnosticsLogPathsSection({
          <div className="flex flex-col sm:flex-row gap-2">
            <input
              type="text"
-              placeholder="Path or wildcard (e.g. C:\Windows\Panther\*.log)"
+              placeholder="Folder, file or wildcard (e.g. C:\Windows\Panther or C:\Windows\Panther\*.log)"
              value={newDiagPath}
              onChange={(e) => setNewDiagPath(e.target.value)}
              onKeyDown={(e) => { if (e.key === "Enter") { e.preventDefault(); addPath(); } }}
@@ -304,7 +304,7 @@ export default function DiagnosticsSection({
          <div className="flex flex-col sm:flex-row gap-2">
            <input
              type="text"
-              placeholder="Path or wildcard (e.g. C:\Windows\Panther\*.log)"
+              placeholder="Folder, file or wildcard (e.g. C:\Windows\Panther or C:\Windows\Panther\*.log)"
              value={newDiagPath}
              onChange={(e) => setNewDiagPath(e.target.value)}
              onKeyDown={(e) => { if (e.key === "Enter") { e.preventDefault(); addTenantPath(); } }}
@@ -410,6 +410,32 @@ describe("validateDiagnosticsPath", () => {
    const r = validateDiagnosticsPath("C:\\Windows\\System32\\winevt\\Logs\\System.evtx", false);
    expect(r.allowed).toBe(true);
  });
+
+  it.each([
+    "C:\\Windows\\System32\\winevt\\Logs\\Security.evtx",
+    "C:\\Windows\\System32\\winevt\\Logs\\security.EVTX",
+    "C:\\Windows\\System32\\winevt\\Logs\\Microsoft-Windows-PowerShell%4Operational.evtx",
+    "C:\\Windows\\System32\\winevt\\Logs\\Windows PowerShell.evtx",
+    "C:\\Windows\\System32\\winevt\\Logs\\Microsoft-Windows-Sysmon%4Operational.evtx",
+    "C:\\Windows\\System32\\winevt\\Logs\\Archive-Security-2026-09-21-10-15-30-123.evtx",
+    "C:\\Install\\Log\\Security.evtx",
+  ])("blocks the hard-blocked event log %s in every mode", (path) => {
+    expect(validateDiagnosticsPath(path, false).allowed).toBe(false);
+    const unrestricted = validateDiagnosticsPath(path, true);
+    expect(unrestricted.allowed).toBe(false);
+    expect(unrestricted.reason).toContain("never readable");
+  });
+
+  it("does not mistake a neighbouring channel for a blocked one", () => {
+    const dsc =
+      "C:\\Windows\\System32\\winevt\\Logs\\Microsoft-Windows-PowerShell-DesiredStateConfiguration-FileDownloadManager%4Operational.evtx";
+    expect(validateDiagnosticsPath(dsc, false).allowed).toBe(true);
+    expect(validateDiagnosticsPath("C:\\Windows\\Logs\\SecurityAudit.evtx", false).allowed).toBe(true);
+  });
+
+  it("leaves an .evtx wildcard allowed — the agent skips blocked files one by one", () => {
+    expect(validateDiagnosticsPath("C:\\Windows\\System32\\winevt\\Logs\\*.evtx", false).allowed).toBe(true);
+  });
 });

 // ---------------------------------------------------------------------------
@@ -457,6 +457,19 @@ export function validateDiagnosticsPath(
    return { allowed: false, reason: `${hardBlockedDiag} is always blocked (protected system path)`, unrestricted: false };
  }

+  // Hard-blocked event logs (even in unrestricted mode). Only a path that names the
+  // file is caught here; for a wildcard the agent skips these files one by one.
+  const blockedChannel = findBlockedEventLogFile(
+    normalizedDir.substring(normalizedDir.lastIndexOf("\\") + 1)
+  );
+  if (blockedChannel) {
+    return {
+      allowed: false,
+      reason: `"${blockedChannel}" is never readable — it carries the audit trail or script-block logging`,
+      unrestricted: false,
+    };
+  }
+
  if (unrestrictedMode) {
    return { allowed: true, reason: "All paths allowed in unrestricted mode (except blocked system paths)", unrestricted: true };
  }
@@ -497,6 +510,22 @@ function matchesChannel(channel: string, prefix: string): boolean {
  return c === p || c.startsWith(p + "/");
 }

+// Windows archives a full channel as "Archive-<file name>-yyyy-MM-dd-HH-mm-ss-fff.evtx".
+const ARCHIVED_EVENT_LOG = /^Archive-(.+)-\d{4}-\d{2}-\d{2}-\d{2}-\d{2}-\d{2}-\d{3}$/i;
+
+/**
+ * The blocked channel an .evtx file name belongs to (live or archived file; "%4" in the
+ * name encodes "/"), or undefined. Mirrors DiagnosticsPathGuards.IsHardBlockedEventLogFile.
+ */
+function findBlockedEventLogFile(fileName: string): string | undefined {
+  if (!fileName.toLowerCase().endsWith(".evtx")) return undefined;
+  let stem = fileName.slice(0, -".evtx".length);
+  const archived = ARCHIVED_EVENT_LOG.exec(stem);
+  if (archived) stem = archived[1];
+  const channel = stem.replace(/%4/g, "/").trim();
+  return BLOCKED_EVENT_LOG_CHANNELS.find((b) => matchesChannel(channel, b));
+}
+
 export function validateEventLogTarget(
  target: string,
  unrestrictedMode: boolean