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Detection rules › Sigma

Potential COLDSTEEL RAT File Indicators

Status
test
Severity
high
Log source
product windows, category file_event
Author
Nasreddine Bencherchali (Nextron Systems)
Source
github.com/SigmaHQ/sigma

Detects the creation of a file named "dllhost.exe" in the "C:\users\public\Documents" directory. Seen being used by the COLDSTEEL RAT in some of its variants.

MITRE ATT&CK coverage

TacticTechniques
PersistenceNo specific technique
StealthNo specific technique

Event coverage

ProviderEventTitle
SysmonEvent ID 11FileCreate

Rule body yaml

title: Potential COLDSTEEL RAT File Indicators
id: c708a93f-46b4-4674-a5b8-54aa6219c5fa
status: test
description: Detects the creation of a file named "dllhost.exe" in the "C:\users\public\Documents\" directory. Seen being used by the COLDSTEEL RAT in some of its variants.
references:
    - https://www.ncsc.gov.uk/static-assets/documents/malware-analysis-reports/cold-steel/NCSC-MAR-Cold-Steel.pdf
author: Nasreddine Bencherchali (Nextron Systems)
date: 2023-04-30
tags:
    - attack.persistence
    - detection.emerging-threats
    - attack.stealth
logsource:
    category: file_event
    product: windows
detection:
    selection:
        TargetFilename: 'C:\users\public\Documents\dllhost.exe'
    condition: selection
falsepositives:
    - Unknown
level: high

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    TargetFilename: 'C:\users\public\Documents\dllhost.exe'

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
TargetFilenameeq
  • C:\users\public\Documents\dllhost.exe