Sigma rule: Webshell Remote Command Execution

Rule

Title

Webshell Remote Command Execution

Status

test

Level

critical

Author

Ilyas Ochkov, Beyu Denis, oscd.community

Date

2019-10-12

Modified

2025-12-05

File

rules/linux/auditd/syscall/lnx_auditd_web_rce.yml

Commit

ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects possible command execution by web application/web shell

Log source

product

linux

service

auditd

definition

Required auditd configuration: -a always,exit -F arch=b32 -S execve -F euid=33 -k detect_execve_www -a always,exit -F arch=b64 -S execve -F euid=33 -k detect_execve_www -a always,exit -F arch=b32 -S execveat -F euid=33 -k detect_execve_www -a always,exit -F arch=b64 -S execveat -F euid=33 -k detect_execve_www Change the number "33" to the ID of your WebServer user. Default: www-data:x:33:33

Detection

selection:
    type: 'SYSCALL'
    SYSCALL:
        - 'execve'
        - 'execveat'
    euid: 33
condition: selection

False positives (as the rule lists them)

• Admin activity
• Crazy web applications

Tags

• attack.persistence
• attack.t1505.003

MITRE ATT&CK ids this rule names

• T1505.003

References

• Personal Experience of the Author
• https://www.vaadata.com/blog/what-is-command-injection-exploitations-and-security-best-practices/

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/linux/auditd/syscall/lnx_auditd_web_rce.yml