Sigma rule: Linux Base64 Encoded Pipe to Shell

Rule

Title

Linux Base64 Encoded Pipe to Shell

Status

test

Level

medium

Author

pH-T (Nextron Systems)

Date

2022-07-26

Modified

2023-06-16

File

rules/linux/process_creation/proc_creation_lnx_base64_execution.yml

Commit

ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects suspicious process command line that uses base64 encoded input for execution with a shell

Log source

product

linux

category

process_creation

Detection

selection_base64:
    CommandLine|contains: 'base64 '
selection_exec:
    - CommandLine|contains:
          - '| bash '
          - '| sh '
          - '|bash '
          - '|sh '
    - CommandLine|endswith:
          - ' |sh'
          - '| bash'
          - '| sh'
          - '|bash'
condition: all of selection_*

False positives (as the rule lists them)

• Legitimate administration activities

Tags

• attack.stealth
• attack.t1140

MITRE ATT&CK ids this rule names

• T1140

References

• https://github.com/arget13/DDexec
• https://www.mandiant.com/resources/blog/barracuda-esg-exploited-globally

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/process_creation/proc_creation_lnx_base64_execution.yml