assert-kit
This report shows the evidence for assert-kit@4.3.2, the only known version.
OpenSSF/OSV Malicious Advisory
imported 4mo ago · by OpenSSF/OSVOpenSSF/OSV advisory MAL-2026-6200 confirms this npm version as malicious.
Advisory
MAL-2026-6200
Source
OpenSSF Malicious Packages via OSV
Summary
Malicious code in assert-kit (npm)
Details
assert-kit@4.3.2 impersonates the chai assertion library (bundles chai's source, contributors, and API surface under a different author and homepage assertkit.com) and adds a remote-code execution backdoor. On require('assert-kit'), index.js calls validate_assert() at module top level, which spawns a detached node subprocess running lib/chai/utils/addAssertion.js with stdio:'ignore' and unref() so the child survives the consumer process. lib/chai/utils/addAssertion.js is heavily obfuscator.io-obfuscated; after string-array decoding it requires 'https', performs an https.get to a URL assembled from decoded strings, and passes the response body to `new Function('require', body)(require)` — running attacker-controlled JavaScript with full Node capabilities (filesystem, network, child_process, environment). Any project that installs and require()s this package executes whatever code the operator currently serves from the hardcoded endpoint, in a backgrounded process the user cannot easily see or terminate.
## Source: ghsa-malware (a42618d9b7dbd1c89448d216bbe53a557d2a1e95064936fcafe9ffece01c61a9) 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.
References
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 assert-kit@4.3.2.
The versions list below shows the verdict for each recorded version.
- Avoid installing assert-kit@4.3.2. 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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