MAL-2026-5189

Dashboard / Malicious Package / MAL-2026-5189

MAL-2026-5189

Summary: Malicious code in arjson (npm)

Details: Source: amazon-inspector (00290c05e0c41a8f51d38c629ade5b3fe76f2a89302db8daac669b0c80d13197) package.json declares `"preinstall": "./.github/scripts/precheck"`, which on `npm install` executes a 976KB UPX-packed Linux ELF binary shipped under `.github/scripts/` (a path designed to look like CI tooling). The binary has no accompanying source, is compressed with UPX (`http://upx.sf.net` banner present in the packed image) to defeat static inspection, and its embedded strings reveal capabilities far beyond anything a JSON serialization library would require: libbpf/eBPF (`LIBBPF_0.0`), kernel tracing (`PTRACE`), netlink socket-diag enumeration (`NETLINK_*_DIAG`, `INODE`), HTTP client primitives (`HTTP/1.1`, `POST`, `DELETE`), GitHub API client (`2022-11-28`), Windows path handling (`USERPROFILE`), and asymmetric crypto (Ed25519, MLKEM, RSA_PKCS1_). Any developer or CI system running `npm install arjson` on Linux will execute opaque packed native code with kernel-level introspection and HTTP-exfiltration capability. The package is advertised as a JSON library; no legitimate purpose exists for shipping a packed eBPF/HTTP-capable preinstall binary. Source: google-open-source-security (146faaf0d97c6a533a969bc3f3f117811f9317dc865ed4ab37f1679842ddeaae) This package was compromised as part of the IronWorm campaign. This campaign executes a malicious binary payload during installation via a preinstall hook. The payload is a Rust-built infostealer that targets developer environments, scanning for and harvesting credentials related to cloud providers, object storage, databases, source-control, package registries, and AI developer tools. It also targets cryptocurrency wallets, specifically injecting a malicious JavaScript hook into the Exodus desktop wallet to capture passwords and recovery phrases. Furthermore, the malware exhibits worm-like behavior by stealing GitHub and NPM credentials to push malicious updates to the victim's repositories and publish trojanized packages, and it uses an eBPF-based kernel rootkit to hide its processes and network connections on Linux systems.

References: http://www.ox.security/blog/ironworm-supply-chain-malware-hits-npm/, https://research.jfrog.com/post/iron-worm-shai-hulud-rustier-cousin/, https://www.npmjs.com/package/arjson/v/0.1.4