Which versions of appsignal are malicious?

The following npm versions of appsignal are flagged malicious: 9999.0.0. Treat any of these as compromised.

How do I remediate appsignal if I installed it?

appsignal 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.

I already installed appsignal — how do I know if it already compromised me?

If appsignal was ever installed, its post-install/runtime payload may have already executed. O3's L7 egress monitoring and runtime eBPF sensors detect the credential exfiltration or command-and-control callback after install and block the malicious outbound channel, so you catch and contain the actual compromise — not just the presence of the package.

Is appsignal part of a known attack campaign?

Yes — appsignal is associated with the IN-MAL-2026-014905 campaign. Packages in the same campaign often share infrastructure and payloads, so check whether any related packages are also in your dependency tree.

How do I find appsignal across my projects, lockfiles, and CI pipelines?

Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for appsignal (version 9999.0.0). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging appsignal across your stack and pipelines.

Malicious package

appsignalnpm

appsignal is a confirmed malicious npm package (MAL-2026-12512) that steals credentials and exfiltrates sensitive data (malicious version 9999.0.0). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in appsignal (npm)

MAL-2026-12512

Immediate action

Remove the package, then rotate any secrets the build/runtime could reach.

npm uninstall appsignal

What this malware does

Package name appsignal shadows the legitimate @appsignal/* scope and is published at version 9999.0.0, a version-number pattern used to outrank private/internal dependencies during resolution. A preinstall script runs automatically on npm install and issues an HTTP GET to the hardcoded bare-IP endpoint http://75.119.137.232:31337/depconfuse, carrying the installer's os.hostname(), os.userInfo().username, process.cwd(), npm_config_registry, and CI repository-slug environment variables (GITHUB_REPOSITORY, CI_PROJECT_PATH, BUILD_REPOSITORY_NAME, BITBUCKET_REPO_FULL_NAME, TRAVIS_REPO_SLUG, DRONE_REPO, BUILDKITE_PIPELINE_SLUG, CIRCLE_PROJECT_REPONAME, JOB_NAME) as query parameters. The endpoint path /depconfuse, the bare-IP destination, the 9999.0.0 version, and the shadowing of an established scope indicate a dependency-confusion reconnaissance probe designed to identify internal build systems that resolve the public name over an intended private package.

Malicious versions

1 flagged

9999.0.0

Indicators of compromise (SHA-256)

ff26e8c679b4035612af78043157ee418aac37aab4eebc5ba54a6e60f204e95c

Detection & response playbook

Credential / info stealer

Find it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for appsignal (version 9999.0.0). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging appsignal across your stack and pipelines.
If you installed it — respond
appsignal 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.
Did it already run?
If appsignal was ever installed, its post-install/runtime payload may have already executed. O3's L7 egress monitoring and runtime eBPF sensors detect the credential exfiltration or command-and-control callback after install and block the malicious outbound channel, so you catch and contain the actual compromise — not just the presence of the package.
How O3 protects you
O3 blocks appsignal before install through its supply-chain scanner, and if it has already run, detects and severs the exfiltration or C2 callback at runtime through L7 egress monitoring and eBPF.

Frequently asked questions

No. appsignal on npm has been identified as a malicious package (version 9999.0.0 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-014905

References

npmjs.com

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks appsignal-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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