{"id":"1f0489be-b496-4ddf-b3a9-5900f2044e9c","title":"Suspicious File Write to SharePoint Layouts Directory","description":"Detects suspicious file writes to SharePoint layouts directory which could indicate webshell activity or post-exploitation.\nThis behavior has been observed in the exploitation of SharePoint vulnerabilities such as CVE-2025-49704, CVE-2025-49706 or CVE-2025-53770.\n","author":"Swachchhanda Shrawan Poudel (Nextron Systems)","status":"experimental","level":"high","date":"2025-07-24","modified":"","tags":["attack.initial-access","attack.t1190","attack.persistence","attack.t1505.003"],"technique_ids":["T1190","T1505.003"],"logsource":{"product":"windows","category":"file_event"},"falsepositives":["Unknown"],"references":["https://unit42.paloaltonetworks.com/microsoft-sharepoint-cve-2025-49704-cve-2025-49706-cve-2025-53770/","https://www.microsoft.com/en-us/security/blog/2025/07/22/disrupting-active-exploitation-of-on-premises-sharepoint-vulnerabilities/"],"source_path":"rules/windows/file/file_event/file_event_win_susp_filewrite_in_sharepoint_layouts_dir.yml","source_sha256":"972534517212498d5e6a30011d4783d4bc823b556d82b5f6969d393b8b5988d6","source_url":"https://github.com/anpa1200/sigma/blob/b249e9683190cffdcaf188ccbfb90bf4759844e1/rules/windows/file/file_event/file_event_win_susp_filewrite_in_sharepoint_layouts_dir.yml","license":"Detection Rule License 1.1","license_url":"https://github.com/SigmaHQ/Detection-Rule-License/blob/main/LICENSE.Detection.Rules.md","yaml":"title: Suspicious File Write to SharePoint Layouts Directory\nid: 1f0489be-b496-4ddf-b3a9-5900f2044e9c\nstatus: experimental\ndescription: |\n    Detects suspicious file writes to SharePoint layouts directory which could indicate webshell activity or post-exploitation.\n    This behavior has been observed in the exploitation of SharePoint vulnerabilities such as CVE-2025-49704, CVE-2025-49706 or CVE-2025-53770.\nreferences:\n    - https://unit42.paloaltonetworks.com/microsoft-sharepoint-cve-2025-49704-cve-2025-49706-cve-2025-53770/\n    - https://www.microsoft.com/en-us/security/blog/2025/07/22/disrupting-active-exploitation-of-on-premises-sharepoint-vulnerabilities/\nauthor: Swachchhanda Shrawan Poudel (Nextron Systems)\ndate: 2025-07-24\ntags:\n    - attack.initial-access\n    - attack.t1190\n    - attack.persistence\n    - attack.t1505.003\nlogsource:\n    product: windows\n    category: file_event\ndetection:\n    selection:\n        Image|endswith:\n            - '\\cmd.exe'\n            - '\\powershell_ise.exe'\n            - '\\powershell.exe'\n            - '\\pwsh.exe'\n            - '\\w3wp.exe'\n        TargetFilename|startswith:\n            - 'C:\\Program Files\\Common Files\\Microsoft Shared\\Web Server Extensions\\'\n            - 'C:\\Program Files (x86)\\Common Files\\Microsoft Shared\\Web Server Extensions\\'\n        TargetFilename|contains:\n            - '\\15\\TEMPLATE\\LAYOUTS\\'\n            - '\\16\\TEMPLATE\\LAYOUTS\\'\n        TargetFilename|endswith:\n            - '.asax'\n            - '.ascx'\n            - '.ashx'\n            - '.asmx'\n            - '.asp'\n            - '.aspx'\n            - '.bat'\n            - '.cmd'\n            - '.cer'\n            - '.config'\n            - '.hta'\n            - '.js'\n            - '.jsp'\n            - '.jspx'\n            - '.php'\n            - '.ps1'\n            - '.vbs'\n    condition: selection\nfalsepositives:\n    - Unknown\nlevel: high\n","validation":"yaml_parsed_not_backend_compiled_or_live_validated","techniques":[{"key":"enterprise/T1190","id":"T1190","name":"Exploit Public-Facing Application","page":"techniques/enterprise/T1190/"},{"key":"enterprise/T1505.003","id":"T1505.003","name":"Web Shell","page":"techniques/enterprise/T1505.003/"}],"data_path":"data/detection-rules/1f0489be-b496-4ddf-b3a9-5900f2044e9c.json","kind":"sigma"}