Claude Cowork VM Boot Image Tamper

Last updated 22 days ago on 2026-08-06
Created 23 days ago on 2026-08-05

About

Detects unexpected modification of Claude Desktop Cowork VM boot images (kernel, initrd, root filesystem). Adversaries with user-context access can rewrite these stored images so later Cowork sessions boot attacker-controlled code inside a virtual instance that host EDR cannot inspect by default.
Tags
Domain: EndpointOS: macOSOS: WindowsUse Case: Threat DetectionTactic: Defense EvasionData Source: Elastic DefendDomain: LLMLanguage: eql
Severity
medium
Risk Score
47
MITRE ATT&CK™

Defense Evasion (TA0005)(external, opens in a new tab or window)

License
Elastic License v2(external, opens in a new tab or window)

Definition

Rule Type
Event Correlation Rule
Integration Pack
Prebuilt Security Detection Rules
Index Patterns
logs-endpoint.events.file-*
Related Integrations

endpoint(external, opens in a new tab or window)

Query
text code block:
file where host.os.type in ("windows", "macos") and event.action in ("creation", "modification", "overwrite", "rename") and event.outcome == "success" and file.path : ( "/Users/*/Library/Application Support/Claude/vm_bundles/claudevm.bundle/initrd", "/Users/*/Library/Application Support/Claude/vm_bundles/claudevm.bundle/initrd.zst", "/Users/*/Library/Application Support/Claude/vm_bundles/claudevm.bundle/vmlinuz", "/Users/*/Library/Application Support/Claude/vm_bundles/claudevm.bundle/vmlinuz.zst", "/Users/*/Library/Application Support/Claude/vm_bundles/claudevm.bundle/rootfs.img", "?:\\Users\\*\\AppData\\Local\\Packages\\Claude_*\\LocalCache\\Roaming\\Claude\\vm_bundles\\claudevm.bundle\\initrd", "?:\\Users\\*\\AppData\\Local\\Packages\\Claude_*\\LocalCache\\Roaming\\Claude\\vm_bundles\\claudevm.bundle\\initrd.zst", "?:\\Users\\*\\AppData\\Local\\Packages\\Claude_*\\LocalCache\\Roaming\\Claude\\vm_bundles\\claudevm.bundle\\vmlinuz", "?:\\Users\\*\\AppData\\Local\\Packages\\Claude_*\\LocalCache\\Roaming\\Claude\\vm_bundles\\claudevm.bundle\\rootfs.vhdx", "?:\\Users\\*\\AppData\\Local\\Packages\\Claude_*\\LocalCache\\Roaming\\Claude\\vm_bundles\\claudevm.bundle\\smol-bin.vhdx" ) and not ( (process.name : "claude.exe" and process.executable : "?:\\Program Files\\WindowsApps\\Claude_*\\app\\claude.exe") or (process.name : ("Claude", "Claude Helper") and process.executable like "/Applications/Claude.app/*") )

Install detection rules in Elastic Security

Detect Claude Cowork VM Boot Image Tamper in the Elastic Security detection engine by installing this rule into your Elastic Stack.

To setup this rule, check out the installation guide for Prebuilt Security Detection Rules(external, opens in a new tab or window).