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Detection rules › Sigma

Small Sieve Malware Potential C2 Communication

Status
test
Severity
critical
Log source
category proxy
Author
Nasreddine Bencherchali (Nextron Systems)
Source
github.com/SigmaHQ/sigma

Detects potential C2 communication related to Small Sieve malware

MITRE ATT&CK coverage

TacticTechniques
Command & ControlNo specific technique

Rule body yaml

title: Small Sieve Malware Potential C2 Communication
id: b0422664-37a4-4e78-949a-4a139309eaf0
status: test
description: Detects potential C2 communication related to Small Sieve malware
references:
    - https://www.ncsc.gov.uk/static-assets/documents/malware-analysis-reports/goofy-guineapig/NCSC-MAR-Goofy-Guineapig.pdf
author: Nasreddine Bencherchali (Nextron Systems)
date: 2023-05-19
tags:
    - attack.command-and-control
    - detection.emerging-threats
logsource:
    category: proxy
detection:
    selection:
        cs-method: 'GET'
        cs-host: 'api.telegram.org'
        cs-uri|contains|all:
            - 'chat_id=2090761833'
            - 'text=com/'
    condition: selection
falsepositives:
    - Unlikely
level: critical

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    cs-method: 'GET'
    cs-host: 'api.telegram.org'
    cs-uri|contains|all:
        - 'chat_id=2090761833'
        - 'text=com/'

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
cs-hosteq
  • api.telegram.org
cs-methodeq
  • GET
cs-urimatch
  • chat_id=2090761833
  • text=com/