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Malicious package

microsoft-agents-auth-servicenpm

Advisory published Updated

microsoft-agents-auth-service is a confirmed malicious npm package (MAL-2026-3322) that steals credentials and exfiltrates sensitive data. Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in microsoft-agents-auth-service (npm)

MAL-2026-3322
Immediate action
Remove the package, then rotate any secrets the build/runtime could reach.
npm uninstall microsoft-agents-auth-service

What this malware does

Malicious npm package published by the microsop threat actor as part of a dependency-confusion campaign that impersonates internal tooling at Microsoft, Google Cloud, and PayPal using inflated semver values (e.g. 99.9.x, 100.1.x) to win npm resolution against private internal packages. All packages in the campaign falsely advertise themselves as "Security Research PoC" / MSRC research and execute on preinstall via node index.js, exfiltrating to disposable webhook.site endpoints.

This package targets Microsoft-internal infrastructure. On install it shells out to harvest /etc/passwd, probe /etc/shadow, locate SSH private keys (id_rsa, *.pem, authorized_keys), enumerate .netrc / .dockercfg, query the AWS IMDS endpoint http://169.254.169.254/latest/user-data, and grep environment variables matching USER|PASS|TOKEN|CREDENTIAL. The collected output is POSTed to https://webhook.site/11b6a711-bdc7-4444-9a0e-ffcb23151e82 tagged status: ULTRA_USER_CREDENTIAL_SCOUT, target: global-microsoft-infra.

The package microsoft-agents-auth-service was found to contain malicious code.

Malicious versions

all versions

Every published version of this package is considered malicious — remove it entirely.

Indicators of compromise (SHA-256)

bef9025a8049b8baa13cd6339e3f0eaed86f5ecaf0d21e053fe88ae0f6014480

Detection & response playbook

Credential / info stealer

  1. Find it

    Search your lockfiles and build artifacts for microsoft-agents-auth-service (all published versions).

  2. If you installed it — respond

    microsoft-agents-auth-service is built to steal secrets, so assume every credential the build or runtime could read is compromised. Remove it from your project and lockfile, then rotate ALL exposed secrets — npm/registry tokens, cloud keys, CI/CD secrets, SSH keys, and any .env values — from a known-clean machine. Audit logs for unauthorized use of those credentials.

  3. Did it already run?

    If microsoft-agents-auth-service was installed, its post-install payload may already have run. Removing the package does not undo that — check outbound connections and credential use from the install window onward.

Frequently asked questions

No. microsoft-agents-auth-service on npm has been identified as a malicious package (all published versions flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Credits

  • Amazon Inspector · finder
  • SafeDep · finder

Detect & block this

O3 blocks microsoft-agents-auth-service-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the credential exfiltration and severs the channel.

Malware detection Runtime egress monitoring

Explore

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microsoft-agents-auth-service (npm) malicious package — MAL-2026-3322 | O3 Security