Winrar Compressing Dump Files

Status: test
Severity: medium
Log source: category process_creation, product windows
Author: Florian Roth (Nextron Systems)
Source: github.com/SigmaHQ/sigma

Detects execution of WinRAR in order to compress a file with a ".dmp"/".dump" extension, which could be a step in a process of dump file exfiltration.

Known false positives

Legitimate use of WinRAR with a command line in which ".dmp" or ".dump" appears accidentally
Legitimate use of WinRAR to compress WER ".dmp" files for troubleshooting

MITRE ATT&CK coverage

Tactic	Techniques
Collection	`T1560.001` Archive Collected Data: Archive via Utility

Telemetry coverage

Provider	Record / event type
Sysmon	Event ID 1: Process creation

Rule body

title: Winrar Compressing Dump Files
id: 1ac14d38-3dfc-4635-92c7-e3fd1c5f5bfc
related:
    - id: ec570e53-4c76-45a9-804d-dc3f355ff7a7
      type: similar
status: test
description: Detects execution of WinRAR in order to compress a file with a ".dmp"/".dump" extension, which could be a step in a process of dump file exfiltration.
references:
    - https://www.crowdstrike.com/blog/overwatch-exposes-aquatic-panda-in-possession-of-log-4-shell-exploit-tools/
author: Florian Roth (Nextron Systems)
date: 2022-01-04
modified: 2023-09-12
tags:
    - attack.collection
    - attack.t1560.001
logsource:
    category: process_creation
    product: windows
detection:
    selection_img:
        - Image|endswith:
              - '\rar.exe'
              - '\winrar.exe'
        - Description: 'Command line RAR'
    selection_extension:
        CommandLine|contains:
            - '.dmp'
            - '.dump'
            - '.hdmp'
    condition: all of selection_*
falsepositives:
    - Legitimate use of WinRAR with a command line in which ".dmp" or ".dump" appears accidentally
    - Legitimate use of WinRAR to compress WER ".dmp" files for troubleshooting
level: medium

Stages and Predicates

Stage 0: `condition`

all of selection_*

Stage 1: `selection_img`

selection_img:
    - Image|endswith:
          - '\rar.exe'
          - '\winrar.exe'
    - Description: 'Command line RAR'

Stage 2: `selection_extension`

selection_extension:
    CommandLine|contains:
        - '.dmp'
        - '.dump'
        - '.hdmp'

Indicators

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`CommandLine`	match	`.dmp` corpus 10 (sigma 8, chronicle 2) `.dump` corpus 3 (sigma 3) `.hdmp` corpus 3 (sigma 3)	`field:"CommandLine" kind:match`
`Description`	eq	`Command line RAR` corpus 3 (sigma 3)	`field:"Description" kind:eq value:"Command line RAR"`
`Image`	ends_with	`\rar.exe` corpus 5 (sigma 5) `\winrar.exe` corpus 6 (sigma 6)	`field:"Image" kind:ends_with`