Detection rules › Sigma

Bitbucket User Login Failure Via SSH

Status
test
Severity
medium
Log source
product bitbucket, service audit
Author
Muhammad Faisal (@faisalusuf)
Source
github.com/SigmaHQ/sigma

Detects SSH user login access failures. Please note that this rule can be noisy and is recommended to use with correlation based on "author.name" field.

MITRE ATT&CK coverage

TacticTechniques
Credential AccessT1110 Brute Force
Lateral MovementT1021.004 Remote Services: SSH

Rule body yaml

title: Bitbucket User Login Failure Via SSH
id: d3f90469-fb05-42ce-b67d-0fded91bbef3
status: test
description: |
    Detects SSH user login access failures.
    Please note that this rule can be noisy and is recommended to use with correlation based on "author.name" field.
references:
    - https://confluence.atlassian.com/bitbucketserver/view-and-configure-the-audit-log-776640417.html
    - https://confluence.atlassian.com/bitbucketserver/enable-ssh-access-to-git-repositories-776640358.html
author: Muhammad Faisal (@faisalusuf)
date: 2024-02-25
tags:
    - attack.lateral-movement
    - attack.credential-access
    - attack.t1021.004
    - attack.t1110
logsource:
    product: bitbucket
    service: audit
    definition: 'Requirements: "Advance" log level is required to receive these audit events.'
detection:
    selection:
        auditType.category: 'Authentication'
        auditType.action: 'User login failed(SSH)'
    condition: selection
falsepositives:
    - Legitimate user wrong password attempts.
level: medium

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    auditType.category: 'Authentication'
    auditType.action: 'User login failed(SSH)'

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
auditType.actioneq
  • User login failed(SSH)
auditType.categoryeq
  • Authentication