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Detection rules › Sigma

Compressed File Creation Via Tar.EXE

Status
test
Severity
low
Log source
product windows, category process_creation
Author
Nasreddine Bencherchali (Nextron Systems), AdmU3
Source
github.com/SigmaHQ/sigma

Detects execution of "tar.exe" in order to create a compressed file. Adversaries may abuse various utilities to compress or encrypt data before exfiltration.

MITRE ATT&CK coverage

TacticTechniques
CollectionT1560.001 Archive Collected Data: Archive via Utility

Event coverage

ProviderEventTitle
SysmonEvent ID 1Process creation

Rule body yaml

title: Compressed File Creation Via Tar.EXE
id: 418a3163-3247-4b7b-9933-dcfcb7c52ea9
status: test
description: |
    Detects execution of "tar.exe" in order to create a compressed file.
    Adversaries may abuse various utilities to compress or encrypt data before exfiltration.
references:
    - https://unit42.paloaltonetworks.com/chromeloader-malware/
    - https://lolbas-project.github.io/lolbas/Binaries/Tar/
    - https://symantec-enterprise-blogs.security.com/blogs/threat-intelligence/cicada-apt10-japan-espionage
author: Nasreddine Bencherchali (Nextron Systems), AdmU3
date: 2023-12-19
tags:
    - attack.collection
    - attack.exfiltration
    - attack.t1560
    - attack.t1560.001
logsource:
    product: windows
    category: process_creation
detection:
    selection_img:
        - Image|endswith: '\tar.exe'
        - OriginalFileName: 'bsdtar'
    selection_create:
        CommandLine|contains:
            - '-c'
            - '-r'
            - '-u'
    condition: all of selection_*
falsepositives:
    - Likely
level: low

Stages and Predicates

Stage 0: condition

all of selection_*

Stage 1: selection_img

selection_img:
    - Image|endswith: '\tar.exe'
    - OriginalFileName: 'bsdtar'

Stage 2: selection_create

selection_create:
    CommandLine|contains:
        - '-c'
        - '-r'
        - '-u'

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
  • -c corpus 7 (sigma 6, splunk 1)
  • -r corpus 13 (sigma 9, kusto 4)
  • -u corpus 6 (sigma 5, splunk 1)
Imageends_with
  • \tar.exe corpus 2 (sigma 2)
OriginalFileNameeq
  • bsdtar corpus 2 (sigma 2)