Query: alert when Detects changes to the PSFactory COM InProcServer32 registry. This technique was used by RomCom to create persistence st
Matching passage: Sigma rule: Detects changes to the PSFactory COM InProcServer32 registry. This technique was used by RomCom to create persistence st. Logsource: windows / registry_set. Rule: title: Potential PSFactoryBuffer COM Hijacking id: 243380fa-11eb-4141-af92-e14925e77c1b status: test description: Detects changes to the PSFactory COM InProcServer32 registry. This technique was used by RomCom to create persistence storing a malicious DLL. references: - https://blogs.blackberry.com/en/2023/06/romcom-resurfaces-targeting-ukraine - https://strontic.github.io/xcyclopedia/library/clsid_C90250F3-4D7D-4991-9B69-A5C5BC1C2AE6.html - https://www.virustotal.com/gui/file/6d3ab9e729bb03ae8ae3fcd824474c5052a165de6cb4c27334969a542c7b261d/detection - https://www.trendmicro.com/en_us/research/23/e/void-rabisu-s-use-of-romcom-backdoor-shows-a-growing-shift-in-th.html author: BlackBerry Threat Research and Intelligence Team - @Joseliyo_Jstnk date: 2023-06-07 modified: 2023-08-17 tags: - attack.privilege-escalation - attack.persistence - attack.t1546.015 logsource: category: registry_set product: windows detection: selection: TargetObject|endswith: \CLSID\{c90250f3-4d7d-4991-9b69-a5c5bc1c2ae6}\InProcServer32\(Default) filter_main: Details: - '%windir%\System32\ActXPrxy.dll' - C:\Windows\System32\ActXPrxy.dll condition: selection and not filter_main falsepositives: - Unknown level: high
Near-miss 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