diff --git a/rules/windows/process_creation/proc_creation_win_regasm_no_flag_or_dll_execution.yml b/rules/windows/process_creation/proc_creation_win_regasm_no_flag_or_dll_execution.yml new file mode 100644 index 000000000..4566412d7 --- /dev/null +++ b/rules/windows/process_creation/proc_creation_win_regasm_no_flag_or_dll_execution.yml @@ -0,0 +1,35 @@ +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.defense-evasion + - 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. +# Note: You can increase after an initial baseline +level: low