Detection rules › Sigma

ZxShell Malware

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

Detects a ZxShell start by the called and well-known function name

Known false positives

  • Unlikely

MITRE ATT&CK coverage

Telemetry coverage

Rule body

title: ZxShell Malware
id: f0b70adb-0075-43b0-9745-e82a1c608fcc
status: test
description: Detects a ZxShell start by the called and well-known function name
references:
    - https://www.hybrid-analysis.com/sample/5d2a4cde9fa7c2fdbf39b2e2ffd23378d0c50701a3095d1e91e3cf922d7b0b16?environmentId=100
    - https://pub-7cb8ac806c1b4c4383e585c474a24719.r2.dev/116309e7121bc8b0e66e4166c06f7b818e1d3629.pdf
author: Florian Roth (Nextron Systems), oscd.community, Jonhnathan Ribeiro
date: 2017-07-20
modified: 2021-11-27
tags:
    - attack.execution
    - attack.stealth
    - attack.t1059.003
    - attack.t1218.011
    - attack.s0412
    - attack.g0001
    - detection.emerging-threats
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith: '\rundll32.exe'
        CommandLine|contains:
            - 'zxFunction'
            - 'RemoteDiskXXXXX'
    condition: selection
falsepositives:
    - Unlikely
level: critical

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    Image|endswith: '\rundll32.exe'
    CommandLine|contains:
        - 'zxFunction'
        - 'RemoteDiskXXXXX'

Indicators

These rows show field, operator, and value matches.

FieldKindValuesSearch
CommandLinematch
  • RemoteDiskXXXXX
  • zxFunction
field:"CommandLine" kind:match
Imageends_with
  • \rundll32.exe corpus 94 (sigma 94)
field:"Image" kind:ends_with value:"\rundll32.exe"