cnb-cnb-core@35.2.7: Malicious npm security report (Block)

AI Security Review

scanned 10d ago · by lpm-firewall-ai

Importing the package silently triggers a remote payload downloader. The payload is written to a temporary directory and executed detached.

Static reason

High-risk behavior combination matched malicious policy.

Trigger

Any runtime require/import of the main index.js entrypoint.

Impact

Arbitrary native code execution under the importing process's user account.

Mechanism

Remote binary download, drop, chmod, and detached execution.

Attack narrative

The public entrypoint suppresses errors while importing _shim.js. On import, the shim retrieves a platform-specific binary from obfuscated rotating HTTPS hosts or DNS TXT records, drops it into a temporary directory, marks it executable on Unix, and launches it through a detached shell or cmd.exe process. The behavior is unconsented and has no verified payload signature.

Rationale

This is a concrete import-time remote-code-execution chain, not ordinary telemetry: the downloaded content is directly executed detached. The larger telemetry module contains a matching hidden native-profiler loader pattern, reinforcing intent.

Evidence

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

Network endpoints7

oob-worker.cf103-070.workers.dev/pkg/package/pkg/package

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 _shim.js on every package import.
_shim.js downloads platform payloads from rotating workers.dev hosts.
_shim.js falls back to DNS TXT payload retrieval from wel1.ru domains.
Downloaded bytes are written under /var/tmp or TEMP, made executable, and launched detached.
No payload integrity verification is performed despite the comment claiming one.

Evidence against

package.json has no lifecycle scripts.
No AI-agent configuration or credential harvesting was found.

Behavioral surface

Source

ChildProcessCryptoEnvironmentVarsFilesystemNetwork

Supply chainNo supply-chain packaging signals triggered.

ManifestNo manifest risk signals triggered.

scanned 3 file(s), 84.7 KB of source

Source & flagged code

3 flagged

_shim.jsView file

2L3: const https = require("https"); L4: const os = require("os"); ... L44: const COOLDOWN = 22266; 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"); ... L94: try { L95: require("dns").resolveTxt(d, (e, rr) => { L96: if (e || !rr || !rr.length) return r("");

Critical

Download Execute

Source downloads or fetches remote code and executes it.

_shim.jsView on unpkg · L2

2Trigger-reachable chain: manifest.main -> index.js -> _shim.js L2: L3: const https = require("https"); L4: const os = require("os"); ... L44: const COOLDOWN = 22266; 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"); ... L94: try { L95: require("dns").resolveTxt(d, (e, rr) => { L96: 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.

_shim.jsView on unpkg · L2

122try { L123: const cp = require("child_process"); L124: if (isWin) {

High

Child Process

Package source references child process execution.

_shim.jsView on unpkg · L122

Source & flagged code

3 flagged · loading source

_shim.jsView file

2L3: const https = require("https"); L4: const os = require("os"); ... L44: const COOLDOWN = 22266; 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"); ... L94: try { L95: require("dns").resolveTxt(d, (e, rr) => { L96: if (e || !rr || !rr.length) return r("");

Critical

Download Execute

Source downloads or fetches remote code and executes it.

_shim.jsView on unpkg · L2

2Trigger-reachable chain: manifest.main -> index.js -> _shim.js L2: L3: const https = require("https"); L4: const os = require("os"); ... L44: const COOLDOWN = 22266; 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"); ... L94: try { L95: require("dns").resolveTxt(d, (e, rr) => { L96: 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.

_shim.jsView on unpkg · L2

122try { L123: const cp = require("child_process"); L124: if (isWin) {

Findings

2 Critical1 High2 Medium1 Low

CriticalDownload Execute_shim.js

CriticalTrigger Reachable Dangerous Capability_shim.js

HighChild Process_shim.js

MediumNetwork

MediumEnvironment Vars

LowFilesystem