sigmamediumHunting

Suspicious Use of /dev/tcp

Detects suspicious command with /dev/tcp

Detection Query

keywords:
  - cat </dev/tcp/
  - exec 3<>/dev/tcp/
  - echo >/dev/tcp/
  - bash -i >& /dev/tcp/
  - sh -i >& /dev/udp/
  - 0<&196;exec 196<>/dev/tcp/
  - exec 5<>/dev/tcp/
  - (sh)0>/dev/tcp/
  - bash -c 'bash -i >& /dev/tcp/
  - echo -e '#!/bin/bash\nbash -i >& /dev/tcp/
condition: keywords

Author

frack113

Created

2021-12-10

Data Sources

linux

Platforms

linux

References

Tags

attack.reconnaissance

Raw Content

title: Suspicious Use of /dev/tcp
id: 6cc5fceb-9a71-4c23-aeeb-963abe0b279c
status: test
description: Detects suspicious command with /dev/tcp
references:
    - https://www.andreafortuna.org/2021/03/06/some-useful-tips-about-dev-tcp/
    - https://book.hacktricks.xyz/shells/shells/linux
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1046/T1046.md#atomic-test-1---port-scan
author: frack113
date: 2021-12-10
modified: 2023-01-06
tags:
    - attack.reconnaissance
logsource:
    product: linux
detection:
    keywords:
        - 'cat </dev/tcp/'
        - 'exec 3<>/dev/tcp/'
        - 'echo >/dev/tcp/'
        - 'bash -i >& /dev/tcp/'
        - 'sh -i >& /dev/udp/'
        - '0<&196;exec 196<>/dev/tcp/'
        - 'exec 5<>/dev/tcp/'
        - '(sh)0>/dev/tcp/'
        - 'bash -c ''bash -i >& /dev/tcp/'
        - 'echo -e ''#!/bin/bash\nbash -i >& /dev/tcp/'
    condition: keywords
falsepositives:
    - Unknown
level: medium