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Detection rules › Sigma

Password Protected Compressed File Extraction Via 7Zip

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

Detects usage of 7zip utilities (7z.exe, 7za.exe and 7zr.exe) to extract password protected zip files.

MITRE ATT&CK coverage

TacticTechniques
CollectionT1560.001 Archive Collected Data: Archive via Utility

Event coverage

ProviderEventTitle
SysmonEvent ID 1Process creation

Rule body yaml

title: Password Protected Compressed File Extraction Via 7Zip
id: b717b8fd-6467-4d7d-b3d3-27f9a463af77
status: test
description: Detects usage of 7zip utilities (7z.exe, 7za.exe and 7zr.exe) to extract password protected zip files.
references:
    - https://blog.cyble.com/2022/06/07/bumblebee-loader-on-the-rise/
author: Nasreddine Bencherchali (Nextron Systems)
date: 2023-03-10
modified: 2026-06-05
tags:
    - attack.collection
    - attack.t1560.001
    - detection.threat-hunting
logsource:
    category: process_creation
    product: windows
detection:
    selection_img:
        - Description|contains: '7-Zip'
        - Image|endswith:
              - '\7z.exe'
              - '\7za.exe'
              - '\7zr.exe'
        - OriginalFileName:
              - '7z.exe'
              - '7za.exe'
              - '7zr.exe'
    selection_password:
        CommandLine|contains|all:
            - ' -p'
            - ' x '
            - ' -o'
    condition: all of selection_*
falsepositives:
    - Legitimate activity is expected since extracting files with a password can be common in some environment.
level: low

Stages and Predicates

Stage 0: condition

all of selection_*

Stage 1: selection_img

selection_img:
    - Description|contains: '7-Zip'
    - Image|endswith:
          - '\7z.exe'
          - '\7za.exe'
          - '\7zr.exe'
    - OriginalFileName:
          - '7z.exe'
          - '7za.exe'
          - '7zr.exe'

Stage 2: selection_password

selection_password:
    CommandLine|contains|all:
        - ' -p'
        - ' x '
        - ' -o'

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
  • -o corpus 7 (sigma 6, chronicle 1)
  • -p corpus 4 (sigma 4)
  • x
Descriptionmatch
  • 7-Zip corpus 3 (sigma 3)
Imageends_with
  • \7z.exe corpus 4 (sigma 4)
  • \7za.exe corpus 3 (sigma 3)
  • \7zr.exe corpus 3 (sigma 3)
OriginalFileNameeq
  • 7z.exe corpus 5 (sigma 4, splunk 1)
  • 7za.exe corpus 5 (sigma 4, splunk 1)
  • 7zr.exe corpus 5 (sigma 4, splunk 1)