Detection rules › Sigma

Renamed Gpg.EXE Execution

Status
test
Severity
high
Log source
product windows, category process_creation
Author
Nasreddine Bencherchali (Nextron Systems), frack113
Source
github.com/SigmaHQ/sigma

Detects the execution of a renamed "gpg.exe". Often used by ransomware and loaders to decrypt/encrypt data.

MITRE ATT&CK coverage

TacticTechniques
ImpactT1486 Data Encrypted for Impact

Event coverage

ProviderEventTitle
SysmonEvent ID 1Process creation

Rule body yaml

title: Renamed Gpg.EXE Execution
id: ec0722a3-eb5c-4a56-8ab2-bf6f20708592
status: test
description: Detects the execution of a renamed "gpg.exe". Often used by ransomware and loaders to decrypt/encrypt data.
references:
    - https://securelist.com/locked-out/68960/
author: Nasreddine Bencherchali (Nextron Systems), frack113
date: 2023-08-09
tags:
    - attack.impact
    - attack.t1486
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        OriginalFileName: 'gpg.exe'
    filter_main_img:
        Image|endswith:
            - '\gpg.exe'
            - '\gpg2.exe'
    condition: selection and not 1 of filter_main_*
level: high

Stages and Predicates

Stage 0: condition

selection and not 1 of filter_main_*

Stage 1: selection

selection:
    OriginalFileName: 'gpg.exe'

Stage 2: not filter_main_img

filter_main_img:
    Image|endswith:
        - '\gpg.exe'
        - '\gpg2.exe'

Exclusions

Top-level NOT(...) conjuncts: predicates this rule actively suppresses.

FieldKindExcluded values
Imageends_with\gpg.exe
Imageends_with\gpg2.exe

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
OriginalFileNameeq
  • gpg.exe corpus 2 (sigma 2)