Query: alert when Detects the execution of "RegAsm.exe" without a commandline flag or file, which might indicate potential process injecti
Matching passage: Sigma rule: Detects the execution of "RegAsm.exe" without a commandline flag or file, which might indicate potential process injecti. Logsource: windows / process_creation. Rule: title: RegAsm.EXE Execution Without CommandLine Flags or Files id: 651f87f7-12db-47f9-84c5-f27b081b94b6 status: experimental description: 'Detects the execution of "RegAsm.exe" without a commandline flag or file, which might indicate potential process injection activity. Usually "RegAsm.exe" should point to a dedicated DLL file or call the help with the "/?" flag. ' references: - https://www.mcafee.com/blogs/other-blogs/mcafee-labs/agent-teslas-unique-approach-vbs-and-steganography-for-delivery-and-intrusion/ - https://www.zscaler.fr/blogs/security-research/threat-actors-exploit-cve-2017-11882-deliver-agent-tesla - https://learn.microsoft.com/en-us/dotnet/framework/tools/regasm-exe-assembly-registration-tool - https://app.any.run/tasks/ea944b89-69d8-49c8-ac1f-5c76ad300db2 - https://www.joesandbox.com/analysis/1467354/0/html author: frack113 date: 2025-06-04 tags: - attack.stealth - attack.t1218.009 logsource: product: windows category: process_creation detection: selection_img: - Image|endswith: \RegAsm.exe - OriginalFileName: RegAsm.exe selection_cli: CommandLine|endswith: - RegAsm - RegAsm.exe - RegAsm.exe" - RegAsm.exe' condition: all of selection_* falsepositives: - Legitimate use of Regasm by developers. level: low
Near-miss passage: Sigma rule: Detects the creation of files with an executable or script extension by an Office application.. Logsource: windows / file_event. Rule: title: File With Uncommon Extension Created By An Office Application id: c7a74c80-ba5a-486e-9974-ab9e682bc5e4 status: test description: Detects the creation of files with an executable or script extension by an Office application. references: - https://thedfirreport.com/2021/03/29/sodinokibi-aka-revil-ransomware/ - https://github.com/vadim-hunter/Detection-Ideas-Rules/blob/02bcbfc2bfb8b4da601bb30de0344ae453aa1afe/Threat%20Intelligence/The%20DFIR%20Report/20210329_Sodinokibi_(aka_REvil)_Ransomware.yaml author: Vadim Khrykov (ThreatIntel), Cyb3rEng (Rule), Nasreddine Bencherchali (Nextron Systems) date: 2021-08-23 modified: 2025-10-17 tags: - attack.t1204.002 - attack.execution logsource: product: windows category: file_event detection: selection1: Image|endswith: - \excel.exe - \msaccess.exe - \mspub.exe - \powerpnt.exe - \visio.exe - \winword.exe selection2: TargetFilename|endswith: - .bat - .cmd - .com - .dll - .exe - .hta - .ocx - .proj - .ps1 - .scf - .scr - .sys - .vbe - .vbs - .wsf - .wsh filter_main_localassembly: TargetFilename|contains: \AppData\Local\assembly\tmp\ TargetFilename|endswith: .dll filter_optional_webservicecache: TargetFilename|contains|all: - C:\Users\ - \AppData\Local\Microsoft\Office\ - \WebServiceCache\AllUsers TargetFilename|endswith: .com filter_optional_webex: Image|endswith: \winword.exe TargetFilename|contains: \AppData\Local\Temp\webexdelta\ TargetFilename|endswith: - .dll - .exe filter_optional_backstageinappnavcache: TargetFilename|contains|all: - C:\Users\ - \AppData\Local\Microsoft\Office\ - \BackstageInAppNavCache\ TargetFilename|endswith: .com condition: all of selection* and not 1 of filter_main_* and not 1 of filter_optional_* falsepositives: - Unknown level: high