registry / Remote code execution / babel-plugin-linaria-css-to-undefined
babel-plugin-linaria-css-to-undefined
This report shows the evidence for babel-plugin-linaria-css-to-undefined@0.3.15. 17 of 17 known versions are blocked or flagged. The newest version, 0.3.17, is blocked. See all versions.
AI Security Review
scanned 3mo ago · by lpm-firewall-aiThe advertised plugin is benign, but the preinstall bootstrap and obfuscated second stage establish concrete malicious install-time behavior.
Static reason
One or more suspicious static signals were detected.; source matched previously finalized malicious package; routed for review; source fingerprint signature matched known malicious package; routed for review
Trigger
npm installation
Impact
Arbitrary code execution and likely credential compromise during installation.
Mechanism
remote payload bootstrap with dynamic eval and credential-oriented logic
Attack narrative
On npm preinstall, setup.mjs invokes an existing Bun binary or downloads a Bun release and executes math_init.js. That obfuscated stage includes fetched-response eval, GitHub-token handling, and process execution, creating an unconsented install-time remote-code path unrelated to the advertised Babel transform.
AI rationale
The advertised plugin is benign, but the preinstall bootstrap and obfuscated second stage establish concrete malicious install-time behavior.
Evidence
package.jsonsetup.mjsmath_init.jslib/index.js
Network endpoints1
github.com/oven-sh/bun/releases/download/bun-v1.3.13/
Decision evidence
public snapshotAI called this Malicious at 99.0% confidence as Malware with low false-positive risk.
Evidence for block
- package.json runs `node setup.mjs` as preinstall.
- setup.mjs downloads Bun then executes math_init.js at install time.
- math_init.js is heavily obfuscated and executes fetched response text with eval.
- math_init.js contains GitHub-token handling and child-process execution.
Evidence against
- lib/index.js is a small, conventional Babel transform.
- README.md describes only the Babel plugin behavior.
Behavioral surface
ChildProcessEvalFilesystemNetworkShell
HighEntropyStringsMinifiedUrlStrings
Source & flagged code
4 flagged · loading sourcepackage.jsonView file
•scripts.preinstall = node setup.mjs
High
Install Time Lifecycle Scripts
Package defines install-time lifecycle scripts.
package.jsonView on unpkgmath_init.jsView file
1// @bun @bun-cjs
L2: var MmgoCP,etDiOOB,JqTtnbZ,bc3Kak,ZQmUTyQ,TTUgga,MDX6yrw,h8wMJNB,CabwE2L,x5ErqV;function WV8StW(MmgoCP,etDiOOB,JqTtnbZ){for(JqTtnbZ=0x0;JqTtnbZ<etDiOOB;JqTtnbZ++)MmgoCP.push(MmgoCP...
Low
Eval
Package source references a known benign dynamic code generation pattern.
math_init.jsView on unpkg · L1setup.mjsView file
•matchType = normalized_sha256
matchedPackage = example-js-project@1.0.11
matchedPath = setup.mjs
matchedIdentity = npm:ZXhhbXBsZS1qcy1wcm9qZWN0:1.0.11
similarity = 1.000
summary = normalized source hash matched finalized malicious source
Findings
3 High2 Medium5 Low
HighInstall Time Lifecycle Scriptspackage.json
HighKnown Malware Source Similaritysetup.mjs
HighKnown Malware Source Fingerprint Signaturesetup.mjs
MediumNetwork
MediumStructural Risk Force Deep Review
LowScripts Present
LowEvalmath_init.js
LowFilesystem
LowHigh Entropy Strings
LowUrl Strings
Affected versions and remediation
This report applies to babel-plugin-linaria-css-to-undefined@0.3.15.
The versions list below shows the verdict for each recorded version.
- Avoid installing babel-plugin-linaria-css-to-undefined@0.3.15. Remove it from direct dependencies and check your lockfile for transitive copies.
- Choose an independently verified alternative or release. This report does not establish that other versions are safe.
- If this version ran, investigate the affected machine and build environment. Rotate credentials it could access and rebuild from a trusted environment.
Evidence last updated: .
Source advisory published: .
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