registry / Remote code execution / express-chai

express-chai

This document describes the management of vulnerabilities for the project and all modules within the organization.

This report shows the evidence for express-chai@3.7.9. 1 of 3 known versions is 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.

AI Security Review

scanned 3mo ago · by lpm-firewall-ai

Direct source inspection confirms an externally controlled payload is dynamically executed. The lack of install hooks does not mitigate runtime remote code execution.

Static reason

One or more suspicious static signals were detected.; source fingerprint signature matched known malicious package; routed for review

Trigger

Import the package and invoke its exported middleware.

Impact

Remote code runs with the consuming application's Node.js privileges.

Mechanism

Remote payload fetch followed by dynamic Function execution.

Attack narrative

The middleware calls lib/caller.js at runtime. That module decodes a hard-coded URL, downloads the cookie field from the response with a fixed header, and passes it to a Function constructor with require available. The endpoint operator can therefore execute arbitrary Node.js code in every application that invokes the middleware.

AI rationale

Direct source inspection confirms an externally controlled payload is dynamically executed. The lack of install hooks does not mitigate runtime remote code execution.

Evidence

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

Network endpoints1

gray-dyane-31.tiiny.site/index.json

Decision evidence

public snapshot

AI called this Malicious at 99.0% confidence as Malware with low false-positive risk.

Evidence for block

index.js invokes lib/caller.js whenever the package middleware is called.
lib/caller.js decodes an embedded remote URL and header values.
lib/caller.js fetches response.data.cookie with axios.
lib/caller.js executes that remote response via Function constructor.
lib/const.js embeds the decoded endpoint configuration.

Evidence against

package.json has no preinstall, install, or postinstall hook.
No local file writes or credential harvesting were confirmed in inspected paths.

Behavioral surface

Source

ChildProcessEnvironmentVarsNetwork

Supply chain

HighEntropyStringsUrlStrings

ManifestNo manifest risk signals triggered.

scanned 17 file(s), 52.1 KB of source, external domains: github.com

Source & flagged code

2 flagged

lib/caller.jsView file

2L3: const axios = require("axios"); L4: const process = require("./const"); ... L6: module.exports = async function getCallers(..._args) { L7: const src = atob(process.env.DEV_API_KEY); L8: const k = atob(process.env.DEV_SECRET_KEY);

Critical

Remote Response Code Execution

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

lib/caller.jsView on unpkg · L2

•matchType = malicious_source_fingerprint_signature signature = dafbad59d657f665 signatureType = suspicious_hashes sourceLabel = Datadog matchedPackage = chai-jsons@3.3.8 matchedPath = lib/caller.js matchedIdentity = npm:Y2hhaS1qc29ucw:3.3.8 similarity = 1.000 shingleOverlap = 12 summary = Datadog malicious npm corpus sample: samples/npm/malicious_intent/chai-jsons/3.3.8/2025-11-19-chai-jsons-v3.3.8.zip

High

Known Malware Source Fingerprint Signature

Source fingerprint signature matches a known malicious package signature; route for source-aware review.

lib/caller.jsView on unpkg

Source & flagged code

2 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

High

Known Malware Source Fingerprint Signature

Source fingerprint signature matches a known malicious package signature; route for source-aware review.

lib/caller.jsView on unpkg

Findings

1 Critical2 High3 Medium3 Low

CriticalRemote Response Code Executionlib/caller.js

HighEval

HighKnown Malware Source Fingerprint Signaturelib/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 express-chai@3.7.9.

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

Avoid installing express-chai@3.7.9. 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: 2026-08-06 23:50:14.427Z (UTC).

Source advisory published: 2026-08-06 19:11:04.000Z (UTC).

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

Versions

3 known versions

3.7.9latestshownMaliciousRemote Code ExecutionBlockPublishedAug 6, 2026, 6:06 PM 3.7.8Clean—AllowPublishedAug 6, 2026, 5:57 PM 3.7.7Clean—AllowPublishedAug 6, 2026, 5:48 PM

AI Security Review

Decision evidence

Source & flagged code

Source & flagged code

Findings

Affected versions and remediation

Versions

Related packages

Other remote code execution packages

Behavioral surface

Source & flagged code

Related packages

Other remote code execution packages