Query: detection rule: Detects a highly relevant Antivirus alert that reports a web shell. It's highly recommended to tune this rule to the spe
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 the creation of a new local user on a Fortinet FortiGate Firewall. The new local user could be used for VPN conn. Logsource: fortigate / event. Rule: title: FortiGate - New Local User Created id: ddbbe845-1d74-43a8-8231-2156d180234d status: experimental description: 'Detects the creation of a new local user on a Fortinet FortiGate Firewall. The new local user could be used for VPN connections. ' references: - https://www.fortiguard.com/psirt/FG-IR-24-535 - https://docs.fortinet.com/document/fortigate/7.6.4/fortios-log-message-reference/398/event - https://docs.fortinet.com/document/fortigate/7.6.4/cli-reference/109120963/config-user-local - https://docs.fortinet.com/document/fortigate/7.6.4/fortios-log-message-reference/44547/44547-logid-event-config-objattr author: Marco Pedrinazzi (@pedrinazziM) (InTheCyber) date: 2025-11-01 tags: - attack.persistence - attack.t1136.001 logsource: product: fortigate service: event detection: selection: action: Add cfgpath: user.local condition: selection falsepositives: - A local user can be created for legitimate purposes. Investigate the user details to determine if it is authorized. level: medium