Detection rules › Sigma

HackTool - CrackMapExec File Indicators

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

Detects file creation events with filename patterns used by CrackMapExec.

MITRE ATT&CK coverage

TacticTechniques
Credential AccessT1003.001 OS Credential Dumping: LSASS Memory

Event coverage

ProviderEventTitle
SysmonEvent ID 11FileCreate

Rule body yaml

title: HackTool - CrackMapExec File Indicators
id: 736ffa74-5f6f-44ca-94ef-1c0df4f51d2a
related:
    - id: 9433ff9c-5d3f-4269-99f8-95fc826ea489
      type: obsolete
status: test
description: Detects file creation events with filename patterns used by CrackMapExec.
references:
    - https://github.com/byt3bl33d3r/CrackMapExec/
author: Nasreddine Bencherchali (Nextron Systems)
date: 2024-03-11
modified: 2024-06-27
tags:
    - attack.credential-access
    - attack.t1003.001
logsource:
    product: windows
    category: file_event
detection:
    selection_path:
        TargetFilename|startswith: 'C:\Windows\Temp\' # The disk extension is hardcoded in the tool.
    selection_names_str:
        TargetFilename|endswith:
            - '\temp.ps1' # https://github.com/byt3bl33d3r/CrackMapExec/blob/3c3e412193cb6d3237abe90c543e5d995bfa4447/cme/modules/keepass_trigger.py#L42C41-L42C68
            - '\msol.ps1' # https://github.com/byt3bl33d3r/CrackMapExec/blob/3c3e412193cb6d3237abe90c543e5d995bfa4447/cme/modules/msol.py#L48C98-L48C106
    selection_names_re:
        - TargetFilename|re: '\\[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}\.txt$' # https://github.com/byt3bl33d3r/CrackMapExec/blob/3c3e412193cb6d3237abe90c543e5d995bfa4447/cme/protocols/wmi/wmiexec.py#L86
        - TargetFilename|re: '\\[a-zA-Z]{8}\.tmp$' # https://github.com/byt3bl33d3r/CrackMapExec/blob/3c3e412193cb6d3237abe90c543e5d995bfa4447/cme/protocols/smb/atexec.py#L145C19-L146
    condition: selection_path and 1 of selection_names_*
falsepositives:
    - Unknown
level: high

Stages and Predicates

Stage 0: condition

selection_path and 1 of selection_names_*

Stage 1: selection_path

selection_path:
    TargetFilename|startswith: 'C:\Windows\Temp\'

Stage 2: selection_names_str

selection_names_str:
    TargetFilename|endswith:
        - '\temp.ps1'
        - '\msol.ps1'

Stage 3: selection_names_re

selection_names_re:
    - TargetFilename|re: '\\[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}\.txt$'
    - TargetFilename|re: '\\[a-zA-Z]{8}\.tmp$'

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
TargetFilenameends_with
  • \msol.ps1
  • \temp.ps1
TargetFilenameregex_match
  • \[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}.txt$
  • \[a-zA-Z]{8}.tmp$
TargetFilenamestarts_with
  • C:\Windows\Temp\