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Detection rules › Sigma

MERCURY APT Activity

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

Detects suspicious command line patterns seen being used by MERCURY APT

MITRE ATT&CK coverage

TacticTechniques
Execution

Telemetry coverage

ProviderRecord / event type
SysmonEvent ID 1: Process creation
Security-AuditingEvent ID 4688: A new process has been created.

Rule body

title: MERCURY APT Activity
id: a62298a3-1fe0-422f-9a68-ffbcbc5a123d
status: test
description: Detects suspicious command line patterns seen being used by MERCURY APT
references:
    - https://www.microsoft.com/security/blog/2022/08/25/mercury-leveraging-log4j-2-vulnerabilities-in-unpatched-systems-to-target-israeli-organizations/
author: Florian Roth (Nextron Systems)
date: 2022-08-26
modified: 2023-03-10
tags:
    - attack.execution
    - attack.t1059.001
    - attack.g0069
    - detection.emerging-threats
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        CommandLine|contains|all:
            - '-exec bypass -w 1 -enc'
            - 'UwB0AGEAcgB0AC0ASgBvAGIAIAAtAFMAYwByAGkAcAB0AEIAbABvAGMAawAgAHsAKABzAGEAcABzACAAKAAiAHAA'  # Start-Job -ScriptBlock
    condition: selection
falsepositives:
    - Unknown
level: high

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    CommandLine|contains|all:
        - '-exec bypass -w 1 -enc'
        - 'UwB0AGEAcgB0AC0ASgBvAGIAIAAtAFMAYwByAGkAcAB0AEIAbABvAGMAawAgAHsAKABzAGEAcABzACAAKAAiAHAA'

Indicators

These rows show field, operator, and value matches.

FieldKindValuesSearch
CommandLinematch
  • -exec bypass -w 1 -enc corpus 2 (sigma 1, kusto 1)
  • UwB0AGEAcgB0AC0ASgBvAGIAIAAtAFMAYwByAGkAcAB0AEIAbABvAGMAawAgAHsAKABzAGEAcABzACAAKAAiAHAA
field:"CommandLine" kind:match