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Improve extension blacklist behavior #1042

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Merged
patrickklaeren merged 1 commit into from
Aug 30, 2025
Merged

Improve extension blacklist behavior #1042

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156 changes: 82 additions & 74 deletions src/Modix.Services/Moderation/AttachmentBlacklistBehavior.cs
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Original file line number Diff line number Diff line change
@@ -1,6 +1,8 @@
#nullable enable

using System.Collections.Generic;
using System.Collections.Immutable;
using System.IO;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
Expand All @@ -21,78 +23,85 @@ namespace Modix.Services.Moderation
public class AttachmentBlacklistBehavior
: INotificationHandler<MessageReceivedNotification>
{
public static readonly IReadOnlyCollection<string> BlacklistedExtensions = new[]
{
".exe",
".dll",
".application",
".msc",
".bat",
".pdb",
".sh",
".com",
".scr",
".msi",
".cmd",
".vbs",
".js",
".reg",
".pif",
".msp",
".hta",
".cpl",
".jar",
".vbe",
".ws",
".wsf",
".wsc",
".wsh",
".ps1",
".ps1xml",
".ps2",
".ps2xml",
".psc1",
".pasc2",
".msh",
".msh1",
".msh2",
".mshxml",
".msh1xml",
".msh2xml",
".scf",
".lnk",
".inf",
".doc",
".xls",
".ppt",
".docm",
".dotm",
".xlsm",
".xltm",
".xlam",
".pptm",
".potm",
".ppam",
".ppsm",
".sldn",
".sb",
".bin",
".com",
".gadget",
".inf1",
".ins",
".inx",
".isu",
".job",
".jse",
".paf",
".rgs",
".sct",
".shb",
".shs",
".u3p",
".vbscript"
};
/// <summary>
/// Gets the set of blacklisted extensions.
/// </summary>
/// <remarks>
/// When adding new extensions, maintain the alphabetical order to improve readability.
/// </remarks>
public static readonly ImmutableHashSet<string> BlacklistedExtensions =
[
".application",
".bat",
".bin",
".cmd",
".com",
".cpl",
".dll",
".doc",
".docm",
".dotm",
".exe",
".gadget",
".hta",
".inf",
".inf1",
".ins",
".inx",
".isu",
".jar",
".job",
".js",
".jse",
".lnk",
".msc",
".msh",
".msh1",
".msh1xml",
".msh2",
".msh2xml",
".mshxml",
".msi",
".msp",
".paf",
".pasc2",
".pdb",
".pdf",
".pif",
".potm",
".ppam",
".ppsm",
".ppt",
".pptm",
".ps1",
".ps1xml",
".ps2",
".ps2xml",
".psc1",
".reg",
".rgs",
".sb",
".scf",
".scr",
".sct",
".sh",
".shb",
".shs",
".sldn",
".u3p",
".vbe",
".vbs",
".vbscript",
".ws",
".wsc",
".wsf",
".wsh",
".xlam",
".xls",
".xlsm",
".xltm",
".zip",
];

public AttachmentBlacklistBehavior(
DesignatedChannelService designatedChannelService,
Expand Down Expand Up @@ -151,8 +160,7 @@ public async Task HandleNotificationAsync(
AttachmentBlacklistLogMessages.SuspiciousAttachmentsSearching(_logger);
var blacklistedFilenames = message.Attachments
.Select(attachment => attachment.Filename.ToLower())
.Where(filename => BlacklistedExtensions
.Any(extension => filename.EndsWith(extension)))
.Where(filename => BlacklistedExtensions.Contains(Path.GetExtension(filename)))
.ToArray();

if(!blacklistedFilenames.Any())
Expand Down
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