atomic-threat-coverage/Atomic_Threat_Coverage/Detection_Rules/win_apt_zxshell.md

Title	ZxShell Malware
Description	Detects a ZxShell start by the called and well-known function name
ATT&CK Tactic	TA0002: Execution TA0005: Defense Evasion
ATT&CK Technique	T1059.003: Windows Command Shell T1059: Command and Scripting Interpreter T1218.011: Rundll32 T1085: Rundll32
Data Needed	DN_0002_4688_windows_process_creation_with_commandline DN_0003_1_windows_sysmon_process_creation
Trigger	T1059.003: Windows Command Shell T1218.011: Rundll32
Severity Level	critical
False Positives	Unlikely
Development Status	Development Status wasn't defined for this Detection Rule yet
References	https://www.hybrid-analysis.com/sample/5d2a4cde9fa7c2fdbf39b2e2ffd23378d0c50701a3095d1e91e3cf922d7b0b16?environmentId=100
Author	Florian Roth
Other Tags	attack.s0412 attack.g0001

Detection Rules

Sigma rule

title: ZxShell Malware
id: f0b70adb-0075-43b0-9745-e82a1c608fcc
description: Detects a ZxShell start by the called and well-known function name
author: Florian Roth
date: 2017/07/20
modified: 2020/08/26
references:
    - https://www.hybrid-analysis.com/sample/5d2a4cde9fa7c2fdbf39b2e2ffd23378d0c50701a3095d1e91e3cf922d7b0b16?environmentId=100
tags:
    - attack.execution
    - attack.t1059.003
    - attack.t1059  # an old one
    - attack.defense_evasion
    - attack.t1218.011
    - attack.t1085  # an old one
    - attack.s0412
    - attack.g0001
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        CommandLine|contains:
            - 'rundll32.exe *,zxFunction*'
            - 'rundll32.exe *,RemoteDiskXXXXX'
    condition: selection
fields:
    - CommandLine
    - ParentCommandLine
falsepositives:
    - Unlikely
level: critical

powershell

Get-WinEvent | where {($_.message -match "CommandLine.*.*rundll32.exe .*,zxFunction.*" -or $_.message -match "CommandLine.*.*rundll32.exe .*,RemoteDiskXXXXX.*") } | select TimeCreated,Id,RecordId,ProcessId,MachineName,Message

es-qs

winlog.event_data.CommandLine.keyword:(*rundll32.exe\\ *,zxFunction* OR *rundll32.exe\\ *,RemoteDiskXXXXX*)

xpack-watcher

curl -s -XPUT -H \'Content-Type: application/json\' --data-binary @- localhost:9200/_watcher/watch/f0b70adb-0075-43b0-9745-e82a1c608fcc <<EOF\n{\n  "metadata": {\n    "title": "ZxShell Malware",\n    "description": "Detects a ZxShell start by the called and well-known function name",\n    "tags": [\n      "attack.execution",\n      "attack.t1059.003",\n      "attack.t1059",\n      "attack.defense_evasion",\n      "attack.t1218.011",\n      "attack.t1085",\n      "attack.s0412",\n      "attack.g0001"\n    ],\n    "query": "winlog.event_data.CommandLine.keyword:(*rundll32.exe\\\\ *,zxFunction* OR *rundll32.exe\\\\ *,RemoteDiskXXXXX*)"\n  },\n  "trigger": {\n    "schedule": {\n      "interval": "30m"\n    }\n  },\n  "input": {\n    "search": {\n      "request": {\n        "body": {\n          "size": 0,\n          "query": {\n            "bool": {\n              "must": [\n                {\n                  "query_string": {\n                    "query": "winlog.event_data.CommandLine.keyword:(*rundll32.exe\\\\ *,zxFunction* OR *rundll32.exe\\\\ *,RemoteDiskXXXXX*)",\n                    "analyze_wildcard": true\n                  }\n                }\n              ],\n              "filter": {\n                "range": {\n                  "timestamp": {\n                    "gte": "now-30m/m"\n                  }\n                }\n              }\n            }\n          }\n        },\n        "indices": [\n          "winlogbeat-*"\n        ]\n      }\n    }\n  },\n  "condition": {\n    "compare": {\n      "ctx.payload.hits.total": {\n        "not_eq": 0\n      }\n    }\n  },\n  "actions": {\n    "send_email": {\n      "throttle_period": "15m",\n      "email": {\n        "profile": "standard",\n        "from": "root@localhost",\n        "to": "root@localhost",\n        "subject": "Sigma Rule \'ZxShell Malware\'",\n        "body": "Hits:\\n{{#ctx.payload.hits.hits}}Hit on {{_source.@timestamp}}:\\n      CommandLine = {{_source.CommandLine}}\\nParentCommandLine = {{_source.ParentCommandLine}}================================================================================\\n{{/ctx.payload.hits.hits}}",\n        "attachments": {\n          "data.json": {\n            "data": {\n              "format": "json"\n            }\n          }\n        }\n      }\n    }\n  }\n}\nEOF\n

graylog

CommandLine.keyword:(*rundll32.exe *,zxFunction* *rundll32.exe *,RemoteDiskXXXXX*)

splunk

(CommandLine="*rundll32.exe *,zxFunction*" OR CommandLine="*rundll32.exe *,RemoteDiskXXXXX*") | table CommandLine,ParentCommandLine

logpoint

CommandLine IN ["*rundll32.exe *,zxFunction*", "*rundll32.exe *,RemoteDiskXXXXX*"]

grep

grep -P '^(?:.*.*rundll32\\.exe .*,zxFunction.*|.*.*rundll32\\.exe .*,RemoteDiskXXXXX.*)'