Malicious code in jscrambler (npm)
Published Sources: OSV
What is affected, what to do
The available sources name no fixed version. Check the vendor guidance in the references below.
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CVSS v3
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Priority (0–325)
The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?
Read in glossary- 20.02 Methodology
Exploit maturity
An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.
Read in glossary- no public PoC known
KEV status
The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.
Read in glossary- —
- Published
Classification under NIS2 and CRA
Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.
NIS2
NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.
Read in glossary- Handle the vulnerability in regular vulnerability handling under Art. 21(2)(e) NIS2.
CRA
The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.
Read in glossary- From 11.12.2027, Annex I Part II CRA requires manufacturers of affected products with digital elements to handle vulnerabilities without delay and provide security updates.
ISO/IEC 27001
ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.
Read in glossary- Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.
Description
Supply-chain compromise of the official jscrambler npm client, a legitimate JavaScript obfuscation tool with roughly 60K downloads per month. Version 8.14.0 was published from the legitimate publisher account (jscrambler_ / info@jscrambler.com), which points to an account or CI compromise rather than a typosquat. Compared to the clean 8.13.0, version 8.14.0 adds a new preinstall hook (node dist/setup.js) and a new 7.5MB dist/intro.js file (entropy 8.00) that is a custom-packed, multi-platform binary container (magic bytes 1b435349 01); both are absent in 8.13.0. At install time, setup.js gunzips the platform-matched payload from intro.js, writes it to a randomly named file under the OS temp directory with the executable bit set (0o755, or a .exe extension on Windows built via String.fromCharCode), then spawns it detached with unref and windowsHide while swallowing all errors. The result is a silent, install-time native-binary dropper. Multiple releases are compromised (8.14.0, 8.16.0, 8.17.0, 8.18.0, 8.20.0); the mechanism above was analyzed on 8.14.0. Version 8.13.0 is clean.
-= Per source details. Do not edit below this line.=-
Source: amazon-inspector (afb577cf150e98ebfe551df006c555204f327432baa3789473981888761a8677)
The package's main entry (dist/index.js) contains a top-level IIFE that runs on every require('jscrambler'). It reads a bundled 7.8 MB sibling file dist/intro.js, validates a custom container header (0x1b 0x43 0x53 0x49 0x01), selects a platform-specific gzip section (linux/win32/darwin), writes the decompressed bytes to os.tmpdir() under a hidden random dot-file name with mode 0755, and spawns the binary detached with stdio ignored and windowsHide, then unrefs the child. Errors are swallowed. The bundled payload dist/intro.js is not JavaScript: it uses a custom multi-platform container and contains strings characteristic of a cryptocurrency-wallet seed-phrase harvester and a browser-session stealer, including the BIP-39 English wordlist marker (bip39_english) and Chromium/BoringSSL TLS internals (ResumptionAttemptedWithVariedEms). Neither README nor CHANGELOG documents any native runtime component, and the CHANGELOG has no entries past 8.13.0. The wrapper's shape (custom magic header, hidden tmp filename, detached spawn, error-swallowed try/catch, undocumented payload) is inconsistent with the package's advertised CLI/API-client purpose and matches a malicious release / account-takeover pattern targeting installer wallets and browser sessions.
Source: ghsa-malware (dd1dd335cffe74c32587c873f4b6d5efd7bf80a5fcecb9bad030662e2a7498c0)
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.