chai-plugin
This report shows the evidence for chai-plugin@4.5.5. 4 of 4 known versions are blocked or flagged. See all versions.
This package appears in our research on the fake chai plugin campaign, with how it works, the full package list and what to do if you installed it.
OpenSSF/OSV Malicious Advisory
imported 4mo ago · by OpenSSF/OSVOpenSSF/OSV advisory MAL-2026-5904 confirms this npm version as malicious.
Advisory
MAL-2026-5904
Source
OpenSSF Malicious Packages via OSV
Summary
Malicious code in chai-plugin (npm)
Details
Package name `chai-plugin` impersonates the popular `chai` assertion library — README and copyright headers reference chaijs.com / chaijs/chai, but the homepage is the lookalike `chaiplugin.com` and the author is unrelated to chai's real maintainer. Two obfuscator.io payloads (hex-named identifiers, rotated string array with a base64+URI custom decoder, control-flow obfuscation, arithmetic self-check) are glued onto otherwise-legitimate chai source. (1) `lib/chai/utils/assertion.js` builds a URL with a query parameter, calls `require('http'|'https').get(url,...)`, accumulates the response body, then executes the bytes via `new Function('require', body)(require)` — an import-time dropper that runs whatever JS the remote server currently serves, with full Node `require` capability. (2) `lib/chai.js` destructures `spawn` from `child_process` and unconditionally invokes a top-level function that runs `spawn(<cmd>, [path.join(__dirname, <sibling>), JSON.stringify(opts)], {detached: true, stdio:...}).unref()`, backgrounding a malicious worker that survives the parent process. Both fire at module load via `index.js -> require('./lib/chai')`. The combination of typosquat name, obfuscation smuggled onto legitimate source, network-fetch-and-eval, and detached subprocess launch is a malicious supply-chain dropper.
Source & flagged code
0 flagged · loading sourceNo flagged code excerpts are attached to this scan.
Findings
1 High
HighOsv Malicious Advisory
Affected versions and remediation
This report applies to chai-plugin@4.5.5.
The versions list below shows the verdict for each recorded version.
- Avoid installing chai-plugin@4.5.5. 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: .
This report uses published external intelligence. The advisory does not provide a separate source-code analysis for each listed version.
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