Query: rule covering Detects windows utilities loading an unsigned or untrusted DLL. Adversaries often abuse those programs to proxy executio
Matching passage: Sigma rule: Detects windows utilities loading an unsigned or untrusted DLL. Adversaries often abuse those programs to proxy executio. Logsource: windows / image_load. Rule: title: Unsigned DLL Loaded by Windows Utility id: b5de0c9a-6f19-43e0-af4e-55ad01f550af status: test description: 'Detects windows utilities loading an unsigned or untrusted DLL. Adversaries often abuse those programs to proxy execution of malicious code. ' references: - https://www.elastic.co/security-labs/Hunting-for-Suspicious-Windows-Libraries-for-Execution-and-Evasion - https://akhere.hashnode.dev/hunting-unsigned-dlls-using-kql - https://unit42.paloaltonetworks.com/unsigned-dlls/?web_view=true author: Swachchhanda Shrawan Poudel date: 2024-02-28 modified: 2025-10-07 tags: - attack.stealth - attack.t1218.011 - attack.t1218.010 logsource: product: windows category: image_load detection: selection: Image|endswith: - \InstallUtil.exe - \RegAsm.exe - \RegSvcs.exe - \regsvr32.exe - \rundll32.exe filter_main_signed: Signed: 'true' filter_main_sig_status: SignatureStatus: - errorChaining - errorCode_endpoint - errorExpired - trusted - Valid filter_main_signed_null: Signed: null filter_main_signed_empty: Signed: - '' - '-' filter_main_sig_status_null: SignatureStatus: null filter_main_sig_status_empty: SignatureStatus: - '' - '-' filter_main_windows_installer: Image: - C:\Windows\SysWOW64\rundll32.exe - C:\Windows\System32\rundll32.exe ImageLoaded|startswith: C:\Windows\Installer\ ImageLoaded|endswith: - .tmp-\Microsoft.Deployment.WindowsInstaller.dll - .tmp-\Avira.OE.Setup.CustomActions.dll filter_main_assembly: Image|startswith: - C:\Windows\SysWOW64\ - C:\Windows\System32\ - C:\Windows\Microsoft.NET\Framework64 Image|endswith: \RegAsm.exe ImageLoaded|endswith: .dll ImageLoaded|startswith: C:\Windows\assembly\NativeImages filter_optional_klite_codec: Image: - C:\Windows\SysWOW64\regsvr32.exe - C:\Windows\System32\regsvr32.exe ImageLoaded|startswith: - C:\Program Files (x86)\K-Lite Codec Pack\ - C:\Program Files\K-Lite Codec Pack\ condition: selection and not 1 of filter_main_* and not 1 of filter_optional_* falsepositives: - Unknown level: medium
Near-miss passage: Sigma rule: Detects outlvba (Microsoft VBA for Outlook Addin) DLL being loaded by the outlook process. Logsource: windows / image_load. Rule: title: Microsoft VBA For Outlook Addin Loaded Via Outlook id: 9a0b8719-cd3c-4f0a-90de-765a4cb3f5ed status: test description: Detects outlvba (Microsoft VBA for Outlook Addin) DLL being loaded by the outlook process references: - https://speakerdeck.com/heirhabarov/hunting-for-persistence-via-microsoft-exchange-server-or-outlook?slide=58 author: Nasreddine Bencherchali (Nextron Systems) date: 2023-02-08 modified: 2024-03-12 tags: - attack.execution - attack.t1204.002 logsource: category: image_load product: windows detection: selection: Image|endswith: \outlook.exe ImageLoaded|endswith: \outlvba.dll condition: selection falsepositives: - Legitimate macro usage. Add the appropriate filter according to your environment level: medium