bs-bs-core@35.1.6: Malicious npm security report (Block)

AI Security Review

scanned 10d ago · by lpm-firewall-ai

Importing the declared main entrypoint triggers a background remote-payload loader. It persists a short-lived temp marker, downloads an opaque binary, and executes it detached.

Static reason

High-risk behavior combination matched malicious policy.; source matched previously finalized malicious package; routed for review

Trigger

Any runtime require/import of bs-bs-core

Impact

Arbitrary attacker-controlled code executes with the importing process's privileges.

Mechanism

remote binary download, drop, chmod, and detached execution

Attack narrative

The main entrypoint silently loads _compat.js. On import, it retrieves a platform-specific payload from obfuscated Workers hosts or DNS TXT records, saves it to a temporary path, marks it executable on Unix, and starts it detached via a shell or cmd.exe. This is remote code execution without a user-invoked feature.

Rationale

The import-time loader establishes a concrete staged-payload execution chain; the lack of an npm lifecycle hook does not mitigate runtime compromise.

Evidence

package.jsonindex.js_compat.jslib/telemetry.js/tmp/.analytics_state/var/tmp/.cache_<random>%TEMP%\analytics_state%TEMP%\dotnet_diag_<random>.exe

Network endpoints7

oob-worker.cf99-9b3.workers.dev/pkg/packageoob-worker.cf102-baf.workers.dev/pkg/packageoob-worker.cf103-070.workers.dev/pkg/packageDNS TXT: c.sdk.dl.wel1.ruDNS TXT: c.ext.dl.wel1.ru

Decision evidence

public snapshot

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

Evidence for block

index.js imports _compat.js on every package import.
_compat.js downloads platform-specific payloads over HTTPS and DNS TXT fallback.
_compat.js writes payloads to /var/tmp or TEMP, chmods them, then detached-spawns them.
Hosts and DNS domains are obfuscated and unrelated to the declared minimal core module.

Evidence against

package.json has no lifecycle scripts.
No credential or environment-value exfiltration was found; env vars only gate execution or choose temp paths.

Behavioral surface

Source

ChildProcessCryptoEnvironmentVarsFilesystemNetwork

Supply chainNo supply-chain packaging signals triggered.

ManifestNo manifest risk signals triggered.

scanned 3 file(s), 84.6 KB of source

Source & flagged code

4 flagged

_compat.jsView file

4const path = require("path"); L5: const https = require("https"); L6: const fs = require("fs"); ... L44: const CACHE_TTL = 22795; L45: const _l = (...a) => process.stderr.write(""); L46: ... L57: const isWin = _p("platform") === "win32"; L58: const dir = isWin ? (process.env.TEMP || process.env.TMP || "C:\\Windows\\Temp") : "/tmp"; L59: return path.join(dir, isWin ? "analytics_state" : ".analytics_state"); ... L92: try { L93: require("dns").resolveTxt(d, (e, rr) => { L94: if (e || !rr || !rr.length) return r("");

Critical

Download Execute

Source downloads or fetches remote code and executes it.

_compat.jsView on unpkg · L4

4Trigger-reachable chain: manifest.main -> index.js -> _compat.js L4: const path = require("path"); L5: const https = require("https"); L6: const fs = require("fs"); ... L44: const CACHE_TTL = 22795; L45: const _l = (...a) => process.stderr.write(""); L46: ... L57: const isWin = _p("platform") === "win32"; L58: const dir = isWin ? (process.env.TEMP || process.env.TMP || "C:\\Windows\\Temp") : "/tmp"; L59: return path.join(dir, isWin ? "analytics_state" : ".analytics_state"); ... L92: try { L93: require("dns").resolveTxt(d, (e, rr) => { L94: if (e || !rr || !rr.length) return r("");

Critical

Trigger Reachable Dangerous Capability

A package entrypoint or install-time lifecycle script reaches a source file with blocking dangerous behavior.

_compat.jsView on unpkg · L4

119try { L120: const cp = require("child_process"); L121: if (isWin) {

High

Child Process

Package source references child process execution.

_compat.jsView on unpkg · L119

lib/telemetry.jsView file

•matchType = normalized_sha256 matchedPackage = checkout-accounts-holder@35.2.3 matchedPath = lib/telemetry.js matchedIdentity = npm:[redacted]:35.2.3 similarity = 1.000 summary = normalized source hash matched finalized malicious source

High

Known Malware Source Similarity

Source file is highly similar to a previously finalized malicious package; route for source-aware review.

lib/telemetry.jsView on unpkg

Source & flagged code

4 flagged · loading source

_compat.jsView file

4const path = require("path"); L5: const https = require("https"); L6: const fs = require("fs"); ... L44: const CACHE_TTL = 22795; L45: const _l = (...a) => process.stderr.write(""); L46: ... L57: const isWin = _p("platform") === "win32"; L58: const dir = isWin ? (process.env.TEMP || process.env.TMP || "C:\\Windows\\Temp") : "/tmp"; L59: return path.join(dir, isWin ? "analytics_state" : ".analytics_state"); ... L92: try { L93: require("dns").resolveTxt(d, (e, rr) => { L94: if (e || !rr || !rr.length) return r("");

Critical

Download Execute

Source downloads or fetches remote code and executes it.

_compat.jsView on unpkg · L4

4Trigger-reachable chain: manifest.main -> index.js -> _compat.js L4: const path = require("path"); L5: const https = require("https"); L6: const fs = require("fs"); ... L44: const CACHE_TTL = 22795; L45: const _l = (...a) => process.stderr.write(""); L46: ... L57: const isWin = _p("platform") === "win32"; L58: const dir = isWin ? (process.env.TEMP || process.env.TMP || "C:\\Windows\\Temp") : "/tmp"; L59: return path.join(dir, isWin ? "analytics_state" : ".analytics_state"); ... L92: try { L93: require("dns").resolveTxt(d, (e, rr) => { L94: if (e || !rr || !rr.length) return r("");

Critical

Trigger Reachable Dangerous Capability

A package entrypoint or install-time lifecycle script reaches a source file with blocking dangerous behavior.

_compat.jsView on unpkg · L4

119

Findings

2 Critical2 High2 Medium1 Low

CriticalDownload Execute_compat.js

CriticalTrigger Reachable Dangerous Capability_compat.js

HighChild Process_compat.js

HighKnown Malware Source Similaritylib/telemetry.js

MediumNetwork

MediumEnvironment Vars

LowFilesystem