Query: detect Detects a highly relevant Antivirus alert that reports a web shell. It's highly recommended to tune this rule to the spe in logs
Matching passage: Sigma rule: Detects a highly relevant Antivirus alert that reports a web shell. It's highly recommended to tune this rule to the spe. Logsource: antivirus. Rule: title: Antivirus - Web Shell Detection Signature id: fdf135a2-9241-4f96-a114-bb404948f736 status: test description: 'Detects a highly relevant Antivirus alert that reports a web shell. It''s highly recommended to tune this rule to the specific strings used by your anti virus solution by downloading a big WebShell repository from e.g. github and checking the matches. This event must not be ignored just because the AV has blocked the malware but investigate, how it came there in the first place. ' references: - https://www.nextron-systems.com/?s=antivirus - https://github.com/tennc/webshell - https://www.virustotal.com/gui/file/bd1d52289203866645e556e2766a21d2275877fbafa056a76fe0cf884b7f8819/detection - https://www.virustotal.com/gui/file/308487ed28a3d9abc1fec7ebc812d4b5c07ab025037535421f64c60d3887a3e8/detection - https://www.virustotal.com/gui/file/7d3cb8a8ff28f82b07f382789247329ad2d7782a72dde9867941f13266310c80/detection - https://www.virustotal.com/gui/file/e841675a4b82250c75273ebf0861245f80c6a1c3d5803c2d995d9d3b18d5c4b5/detection - https://www.virustotal.com/gui/file/a80042c61a0372eaa0c2c1e831adf0d13ef09feaf71d1d20b216156269045801/detection - https://www.virustotal.com/gui/file/b219f7d3c26f8bad7e175934cd5eda4ddb5e3983503e94ff07d39c0666821b7e/detection - https://www.virustotal.com/gui/file/b8702acf32fd651af9f809ed42d15135f842788cd98d81a8e1b154ee2a2b76a2/detection - https://www.virustotal.com/gui/file/13ae8bfbc02254b389ab052aba5e1ba169b16a399d9bc4cb7414c4a73cd7dc78/detection author: Florian Roth (Nextron Systems), Arnim Rupp date: 2018-09-09 modified: 2026-06-29 tags: - attack.persistence - attack.t1505.003 logsource: category: antivirus detection: selection: - Signature|startswith: - ASP. - IIS/BackDoor - JAVA/Backdoor - JSP. - Perl. - PHP. - Troj/ASP - Troj/JSP - Troj/PHP - VBS/Uxor - Signature|contains: - ASP_ - 'ASP:' - ASP.Agent - ASP/ - Aspdoor - ASPXSpy - Backdoor.ASP - Backdoor.Java - Backdoor.JSP - Backdoor.PHP - Backdoor.VBS - Backdoor/ASP - Backdoor/Java - Backdoor/JSP - Backdoor/PHP - Backdoor/VBS - C99shell - Chopper - filebrowser - JSP_ - 'JSP:' - JSP.Agent - JSP/ - 'Perl:' - Perl/ - PHP_ - 'PHP:' - PHP.Agent - PHP/ - PHPShell - PShlSpy - SinoChoper - Trojan.ASP - Trojan.JSP - Trojan.PHP - Trojan.VBS - VBS.Agent - VBS/Agent - Webshell condition: selection falsepositives: - Unlikely level: high
Near-miss passage: Sigma rule: Detects Obfuscated use of Environment Variables to execute PowerShell. Logsource: windows / ps_module. Rule: title: Invoke-Obfuscation VAR+ Launcher - PowerShell Module id: 6bfb8fa7-b2e7-4f6c-8d9d-824e5d06ea9e related: - id: 0adfbc14-0ed1-11eb-adc1-0242ac120002 type: derived status: test description: Detects Obfuscated use of Environment Variables to execute PowerShell references: - https://github.com/SigmaHQ/sigma/issues/1009 author: Jonathan Cheong, oscd.community date: 2020-10-15 modified: 2024-04-05 tags: - attack.stealth - attack.t1027 - attack.execution - attack.t1059.001 logsource: product: windows category: ps_module definition: 0ad03ef1-f21b-4a79-8ce8-e6900c54b65b detection: selection_4103: Payload|re: cmd.{0,5}(?:/c|/r)(?:\s|)"set\s[a-zA-Z]{3,6}.*(?:\{\d\}){1,}\\"\s+?-f(?:.*\)){1,}.*" condition: selection_4103 falsepositives: - Unknown level: high