Query: Sigma YAML for windows / file_event
Matching passage: Sigma rule: Detects dropped files with double extensions, which is often used by malware as a method to abuse the fact that Windows. Logsource: windows / file_event. Rule: title: Suspicious Double Extension Files id: b4926b47-a9d7-434c-b3a0-adc3fa0bd13e related: - id: 1cdd9a09-06c9-4769-99ff-626e2b3991b8 type: derived - id: 3215aa19-f060-4332-86d5-5602511f3ca8 type: similar status: test description: Detects dropped files with double extensions, which is often used by malware as a method to abuse the fact that Windows hide default extensions by default. references: - https://www.crowdstrike.com/blog/meet-crowdstrikes-adversary-of-the-month-for-june-mustang-panda/ - https://www.anomali.com/blog/china-based-apt-mustang-panda-targets-minority-groups-public-and-private-sector-organizations - https://www.cybereason.com/blog/research/a-bazar-of-tricks-following-team9s-development-cycles - https://twitter.com/malwrhunterteam/status/1235135745611960321 - https://twitter.com/luc4m/status/1073181154126254080 - https://cloud.google.com/blog/topics/threat-intelligence/cybercriminals-weaponize-fake-ai-websites - https://vipre.com/blog/svg-phishing-attacks-the-new-trick-in-the-cybercriminals-playbook/ author: Nasreddine Bencherchali (Nextron Systems), frack113 date: 2022-06-19 modified: 2026-03-31 tags: - attack.stealth - attack.t1036.007 logsource: category: file_event product: windows detection: selection_gen: TargetFilename|endswith: - .exe - .iso - .rar - .svg - .zip TargetFilename|contains: - .doc. - .docx. - .gif. - .jpeg. - .jpg. - .mp3. - .mp4. - .pdf. - .png. - .ppt. - .pptx. - .rtf. - .svg. - .txt. - .xls. - .xlsx. selection_exe: TargetFilename|endswith: - .rar.exe - .zip.exe filter_icons_linux: TargetFilename|startswith: /usr/share/icons/ condition: 1 of selection_* and not 1 of filter_* falsepositives: - Unlikely level: high
Near-miss passage: Sigma rule: Detects process access events where WerFaultSecure accesses MsMpEng.exe with dbgcore.dll or dbghelp.dll in the call trac. Logsource: windows / process_access. Rule: title: Suspicious Process Access of MsMpEng by WerFaultSecure - EDR-Freeze id: 387df17d-3b04-448f-8669-9e7fd5e5fd8c related: - id: 8a2f4b1c-3d5e-4f7a-9b2c-1e4f6d8a9c2b type: similar - id: 1f0b4cac-9c81-41f4-95d0-8475ff46b3e2 type: similar status: experimental description: 'Detects process access events where WerFaultSecure accesses MsMpEng.exe with dbgcore.dll or dbghelp.dll in the call trace, indicating potential EDR freeze techniques. This technique leverages WerFaultSecure.exe running as a Protected Process Light (PPL) with WinTCB protection level to call MiniDumpWriteDump and suspend EDR/AV processes, allowing malicious activity to execute undetected during the suspension period. ' references: - https://blog.axelarator.net/hunting-for-edr-freeze/ author: Swachchhanda Shrawan Poudel (Nextron Systems) date: 2025-11-27 tags: - attack.defense-impairment - attack.t1685 logsource: category: process_access product: windows definition: "Requires Sysmon Event ID 10 (ProcessAccess) with CallTrace enabled.\nExample sysmon config snippet with grouping,\ \ as logging individual ProcessAccess events can generate excessive logs:\n<ProcessAccess onmatch=\"include\">\n <Rule\ \ groupRelation=\"and\">\n <TargetImage condition=\"end with\">\\MsMpEng.exe</TargetImage>\n <SourceImage condition=\"\ end with\">\\WerFaultSecure.exe</SourceImage>\n </Rule>\n</ProcessAccess>\n" detection: selection: SourceImage|endswith: \WerFaultSecure.exe TargetImage|endswith: \MsMpEng.exe CallTrace|contains: - \dbgcore.dll - \dbghelp.dll condition: selection falsepositives: - Legitimate Windows Error Reporting operations level: high regression_tests_path: regression_data/rules/windows/process_access/proc_access_win_werfaultsecure_msmpeng_access/info.yml