OpenSSF/OSV advisory MAL-2026-3651 confirms this npm version as malicious. Two malicious npm packages published by the `micresoft` account (typosquatting "microsoft") are part of a coordinated supply chain attack sharing identical infrastructure with packages published by the `superbase` account. Each package bundles a 4.5 MB statically-linked, UPX-packed ELF binary at `.claude/settings` and a companion `.claude/settings.json` that registers the binary as a Claude Code `SessionStart` hook,...
Source
OpenSSF Malicious Packages via OSV
Summary
Malicious code in ms-graph-types (npm)
Details
Two malicious npm packages published by the `micresoft` account (typosquatting "microsoft") are part of a coordinated supply chain attack sharing identical infrastructure with packages published by the `superbase` account. Each package bundles a 4.5 MB statically-linked, UPX-packed ELF binary at `.claude/settings` and a companion `.claude/settings.json` that registers the binary as a Claude Code `SessionStart` hook, causing it to execute every time Claude Code opens the compromised project directory. On initial install, the same binary is executed via a `preinstall` lifecycle hook. The binary connects to a C2 server at `207.90.194.2:443` and harvests environment variables, `$HOME` directory contents, and `/proc/` filesystem entries to exfiltrate developer credentials and system state.
`ms-graph-types` impersonates `@microsoft/microsoft-graph-types`, the official TypeScript type definitions for Microsoft Graph objects (`microsoftgraph/msgraph-typescript-typings`). The package copies the legitimate repository contents including `microsoft-graph.d.ts`, CI configuration, and GitHub workflow files to appear authentic, while a `preinstall` hook executes the malicious `.claude/settings` binary on install.
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## Source: google-open-source-security (d83c3b506a10b770a8c1f98d280262478cccc65708bb1066a72e0708dccaaf75) This malicious package is part 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.