Malicious code in webpack-cache-clean (npm)
--- _-= Per source details. Do not edit below this line.=-_ ## Source: amazon-inspector (8f8656d094ec59721c08eb72a1ec8f1530cd07985edf705032926dd9a19461d9) On `npm install`, the package runs a postinstall hook (`node -e "require('./loader.js')"`) that spawns a detached child process. The child decodes an obfuscated base64 URL (mislabeled as 'hex' with large whitespace padding) resolving to https://jsonkeeper.com/b/L435A, an anonymous JSON paste host, performs an HTTPS GET, extracts JavaScript source from a `manifest.session` field, writes it to a temp file, and `require()`s it — with no signature, hash, or pinned-version check. The fetched code runs with the installer's privileges and can be changed by the attacker between fetches. The package metadata is also inconsistent: the package name is `webpack-cache-clean`, the README is titled `webpack-cache-plugin`, the repository URL points at `webpack-tools/webpack-cache-plugin`, and the author is the generic `Webpack Tools` — a cover story to lure installers searching for legitimate webpack cache tooling. This satisfies install-time-rce: attacker-controlled, unpinned, obfuscated remote code execution fires automatically on default install. ## Source: ghsa-malware (6f98923d9f08741f534522f4b816b09d5953f8d73ddbaef49710ba42236a9cff) Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.
AI Analysis
Technical Summary
The 'webpack-cache-clean' npm package version 0.1.4 includes a postinstall hook that spawns a detached child process which decodes an obfuscated base64 URL pointing to an anonymous JSON paste site. It fetches JavaScript code from the 'manifest.session' field of the JSON response, writes it to a temporary file, and executes it via require(), all without signature verification or version pinning. This allows attacker-controlled remote code execution at install time. The package metadata is inconsistent and misleading, designed to impersonate legitimate webpack cache tools. This behavior constitutes an install-time remote code execution vulnerability with attacker-controlled payloads.
Potential Impact
Installation of the affected package version results in automatic execution of attacker-controlled code with the privileges of the user performing the install. This can lead to full system compromise, including theft of secrets and keys. Because the malicious code is fetched dynamically and can be changed by the attacker, the threat is persistent and can evolve. Removal of the package alone does not guarantee eradication of all malicious artifacts or backdoors introduced by the attacker.
Mitigation Recommendations
No official patch or fix is currently available for this malicious package. The recommended mitigation is to immediately remove the 'webpack-cache-clean' package version 0.1.4 from all systems. Assume any system that installed this package is fully compromised and rotate all secrets and keys from a secure, uncompromised environment. Avoid installing packages with suspicious or inconsistent metadata and verify package authenticity before installation.
Malicious code in webpack-cache-clean (npm)
Description
--- _-= Per source details. Do not edit below this line.=-_ ## Source: amazon-inspector (8f8656d094ec59721c08eb72a1ec8f1530cd07985edf705032926dd9a19461d9) On `npm install`, the package runs a postinstall hook (`node -e "require('./loader.js')"`) that spawns a detached child process. The child decodes an obfuscated base64 URL (mislabeled as 'hex' with large whitespace padding) resolving to https://jsonkeeper.com/b/L435A, an anonymous JSON paste host, performs an HTTPS GET, extracts JavaScript source from a `manifest.session` field, writes it to a temp file, and `require()`s it — with no signature, hash, or pinned-version check. The fetched code runs with the installer's privileges and can be changed by the attacker between fetches. The package metadata is also inconsistent: the package name is `webpack-cache-clean`, the README is titled `webpack-cache-plugin`, the repository URL points at `webpack-tools/webpack-cache-plugin`, and the author is the generic `Webpack Tools` — a cover story to lure installers searching for legitimate webpack cache tooling. This satisfies install-time-rce: attacker-controlled, unpinned, obfuscated remote code execution fires automatically on default install. ## Source: ghsa-malware (6f98923d9f08741f534522f4b816b09d5953f8d73ddbaef49710ba42236a9cff) Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.
Affected software
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AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The 'webpack-cache-clean' npm package version 0.1.4 includes a postinstall hook that spawns a detached child process which decodes an obfuscated base64 URL pointing to an anonymous JSON paste site. It fetches JavaScript code from the 'manifest.session' field of the JSON response, writes it to a temporary file, and executes it via require(), all without signature verification or version pinning. This allows attacker-controlled remote code execution at install time. The package metadata is inconsistent and misleading, designed to impersonate legitimate webpack cache tools. This behavior constitutes an install-time remote code execution vulnerability with attacker-controlled payloads.
Potential Impact
Installation of the affected package version results in automatic execution of attacker-controlled code with the privileges of the user performing the install. This can lead to full system compromise, including theft of secrets and keys. Because the malicious code is fetched dynamically and can be changed by the attacker, the threat is persistent and can evolve. Removal of the package alone does not guarantee eradication of all malicious artifacts or backdoors introduced by the attacker.
Mitigation Recommendations
No official patch or fix is currently available for this malicious package. The recommended mitigation is to immediately remove the 'webpack-cache-clean' package version 0.1.4 from all systems. Assume any system that installed this package is fully compromised and rotate all secrets and keys from a secure, uncompromised environment. Avoid installing packages with suspicious or inconsistent metadata and verify package authenticity before installation.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- MAL-2026-5578
- Osv Schema Version
- 1.7.4
- Aliases
- ["GHSA-82q4-cw9w-vjj4"]
- Ecosystems
- ["npm"]
- Database Specific Severity
- null
- Cvss Version
- null
Threat ID: 6a4c340d27e9c797195f7188
Added to database: 07/06/2026, 23:02:37 UTC
Last enriched: 07/06/2026, 23:17:06 UTC
Last updated: 07/18/2026, 17:27:21 UTC
Views: 9
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