Hunting For Persistence Via Wmi Subscriptions

What it does

When your agent uses it

• Malicious code execution on system events
• Investigating fileless
• Trigger-based persistence on Windows hosts
• Auditing WMI repository contents for malicious event subscriptions

Example prompts

• “Use the hunting-for-persistence-via-wmi-subscriptions skill to hunt for adversary persistence via WMI event subscriptions (MITRE T1546.003) by…”
• “/hunting-for-persistence-via-wmi-subscriptions”

Requirements

• Python 3

Workflow steps

7 steps, taken from the first numbered list in SKILL.md.

1. 1Enumerate Existing WMI Subscriptions: Query all permanent WMI event subscriptions on target systems. A clean system typically has very few…
2. 2Monitor WMI Event Creation (Sysmon 19/20/21): Sysmon Event 19 captures WmiEventFilter activity, Event 20 captures WmiEventConsumer…
3. 3Analyze Consumer Types: Focus on ActiveScriptEventConsumer (runs VBScript/JScript) and CommandLineEventConsumer (executes commands)…
4. 4Check Event Filter Triggers: Examine what triggers the subscription. Common malicious triggers include system startup…
5. 5Investigate WmiPrvSe.exe Child Processes: When a WMI subscription fires, the action is executed by WmiPrvSe.exe. Hunt for unusual child…
6. 6Correlate with MOF Compilation: Detect mofcomp.exe usage which compiles MOF files to create WMI subscriptions programmatically.
7. 7Validate and Respond: Confirm malicious subscriptions, remove them, and trace back to the initial infection vector.

What it can do on your machine

Read from SKILL.md and the folder at commit 54a7988. It shows what the files ask for, not the result of running them.

• Tool permissions

  Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

  From allowed-tools in the SKILL.md frontmatter.

• Runs code

  Ships 2 files in scripts/ (Python), which the agent can run.

  From the folder's file list and the shell code blocks in SKILL.md.

• Network

  No URLs in SKILL.md.

  From URLs in SKILL.md, links to its own repository left out.

• Credentials

  Names no API keys, tokens, secrets or passwords.

  From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Hunting For Persistence Via Wmi Subscriptions loads about 1.5k tokens when it runs, and up to ~3.5k if it reads all its reference files. Until then it costs about 105 tokens; SKILL.md has 417 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it

~105

When it runs · the whole SKILL.md, loaded when a task matches

~1.5k

With references · SKILL.md plus every file in references/, read only if the agent opens them

~3.5k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); the scripts in this folder are not scanned.

SKILL.md

The full file from mukul975/Anthropic-Cybersecurity-Skills at commit 54a7988, republished under its Apache-2.0 licence (© mukul975). 417 words, ~1,535 tokens.

name

hunting-for-persistence-via-wmi-subscriptions

description

Hunts for adversary persistence via WMI event subscriptions (MITRE T1546.003) by monitoring the creation of WMI event filters, consumers, and filter-to-consumer bindings that trigger malicious code execution on system events. Use when investigating fileless, trigger-based persistence on Windows hosts or auditing WMI repository contents for malicious event subscriptions.

domain

cybersecurity

subdomain

threat-hunting

tags

threat-hunting, wmi-persistence, mitre-t1546-003, event-subscription, windows, endpoint-detection

version

1.0

author

mahipal

license

Apache-2.0

d3fend_techniques

Application Protocol Command Analysis, Network Isolation, Network Traffic Analysis, Client-server Payload Profiling, Platform Monitoring

nist_csf

DE.CM-01, DE.AE-02, DE.AE-07, ID.RA-05

mitre_attack

T1046, T1057, T1082, T1083, T1547

index=sysmon (EventCode=19 OR EventCode=20 OR EventCode=21)
| eval event_type=case(EventCode=19, "EventFilter", EventCode=20, "EventConsumer", EventCode=21, "FilterToConsumerBinding")
| table _time Computer User event_type EventNamespace Name Query Destination Operation

index=wineventlog source="Microsoft-Windows-WMI-Activity/Operational" EventCode=5861
| table _time Computer NamespaceName Operation PossibleCause

Get-WmiObject -Namespace root\subscription -Class __EventFilter
Get-WmiObject -Namespace root\subscription -Class __EventConsumer
Get-WmiObject -Namespace root\subscription -Class __FilterToConsumerBinding

DeviceProcessEvents
| where Timestamp > ago(7d)
| where InitiatingProcessFileName =~ "wmiprvse.exe"
| where FileName in~ ("cmd.exe", "powershell.exe", "wscript.exe", "cscript.exe", "mshta.exe", "rundll32.exe")
| project Timestamp, DeviceName, FileName, ProcessCommandLine

title: WMI Event Subscription Persistence
status: stable
logsource:
    product: windows
    category: wmi_event
detection:
    selection_consumer:
        EventID: 20
        Destination|contains:
            - 'ActiveScriptEventConsumer'
            - 'CommandLineEventConsumer'
    condition: selection_consumer
level: high
tags:
    - attack.persistence
    - attack.t1546.003

Hunt ID: TH-WMI-[DATE]-[SEQ]
Host: [Hostname]
Subscription Name: [Filter/Consumer name]
Filter Query: [WQL trigger condition]
Consumer Type: [ActiveScript/CommandLine]
Consumer Action: [Script content or command]
Binding: [Filter-to-Consumer link]
Created: [Timestamp]
User Context: [SYSTEM/User]
Risk Level: [Critical/High/Medium/Low]

© mukul975, Apache-2.0. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

SKILL.md and 7 other files (scripts, references, assets) in skills/hunting-for-persistence-via-wmi-subscriptions of mukul975/Anthropic-Cybersecurity-Skills.

• SKILL.md
• LICENSE
• assets/template.md
• references/api-reference.md
• references/standards.md
• references/workflows.md
• scripts/agent.py
• scripts/process.py

Open the folder on GitHubat commit 54a7988