Detection rules › Sigma

Ursnif Redirection Of Discovery Commands

Status
test
Severity
high
Log source
category process_creation, product windows
Author
@kostastsale
Source
github.com/SigmaHQ/sigma

Detects the redirection of Ursnif discovery commands as part of the initial execution of the malware.

Known false positives

  • Unlikely

MITRE ATT&CK coverage

Telemetry coverage

Rule body

title: Ursnif Redirection Of Discovery Commands
id: 7aaa5739-12fc-41aa-b98b-23ec27d42bdf
status: test
description: |
    Detects the redirection of Ursnif discovery commands as part of the initial execution of the malware.
references:
    - Internal Research
author: '@kostastsale'
date: 2023-07-16
tags:
    - attack.execution
    - attack.t1059
    - detection.emerging-threats
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        ParentImage|endswith: '\explorer.exe'
        Image|endswith: '\cmd.exe'
        CommandLine|contains|all:
            - '/C '
            - ' >> *\AppData\local\temp\*.bin'
    condition: selection
falsepositives:
    - Unlikely
level: high

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    ParentImage|endswith: '\explorer.exe'
    Image|endswith: '\cmd.exe'
    CommandLine|contains|all:
        - '/C '
        - ' >> *\AppData\local\temp\*.bin'

Indicators

These rows show field, operator, and value matches.

FieldKindValuesSearch
CommandLinematch
  • >> *\AppData\local\temp\*.bin
  • /C corpus 4 (sigma 4)
field:"CommandLine" kind:match
Imageends_with
  • \cmd.exe corpus 130 (sigma 130)
field:"Image" kind:ends_with value:"\cmd.exe"
ParentImageends_with
  • \explorer.exe corpus 13 (sigma 13)
field:"ParentImage" kind:ends_with value:"\explorer.exe"