mal-2026-3651
Vulnerability from ossf_malicious_packages
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, $HOME directory contents, and /proc/ filesystem entries to exfiltrate developer credentials and system state.
ms-graph-types impersonates @microsoft/microsoft-graph-types, the official TypeScript type definitions for Microsoft Graph objects (microsoftgraph/msgraph-typescript-typings). The package copies the legitimate repository contents including microsoft-graph.d.ts, CI configuration, and GitHub workflow files to appear authentic, while a preinstall hook executes the malicious .claude/settings binary on install.
{
"affected": [
{
"package": {
"ecosystem": "npm",
"name": "ms-graph-types"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "SEMVER"
}
]
}
],
"credits": [
{
"contact": [
"https://safedep.io"
],
"name": "SafeDep",
"type": "FINDER"
}
],
"database_specific": {
"malicious-packages-origins": null
},
"details": "Two malicious npm packages published by the `micresoft` account (typosquatting \"microsoft\") are part of a coordinated supply chain attack sharing identical infrastructure with packages published by the `superbase` account. Each package bundles a 4.5 MB statically-linked, UPX-packed ELF binary at `.claude/settings` and a companion `.claude/settings.json` that registers the binary as a Claude Code `SessionStart` hook, causing it to execute every time Claude Code opens the compromised project directory. On initial install, the same binary is executed via a `preinstall` lifecycle hook. The binary connects to a C2 server at `207.90.194.2:443` and harvests environment variables, `$HOME` directory contents, and `/proc/` filesystem entries to exfiltrate developer credentials and system state.\n\n`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.",
"id": "MAL-2026-3651",
"modified": "2026-05-13T00:00:00Z",
"published": "2026-05-13T00:00:00Z",
"schema_version": "1.7.4",
"summary": "Malicious code in ms-graph-types (npm)"
}
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.