NIST deprecates RSA-2048 from 2030. Find every one of them before attackers do.
Malicious package

my-ctf-helper-script-9921npm

Advisory published Updated

my-ctf-helper-script-9921 is a confirmed malicious npm package (MAL-2026-16365) that executes malicious code on install (malicious version 1.0.0). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in my-ctf-helper-script-9921 (npm)

MAL-2026-16365
Immediate action
Remove the package, then rotate any secrets the build/runtime could reach.
npm uninstall my-ctf-helper-script-9921

What this malware does

On require/import, the package's main module executes a top-level fetch to the hardcoded collector URL https://webhook.site/99e9df7b-fe86-4c60-822a-5352b1f9edf0/, appending document.cookie as a query-string parameter. The package has no other advertised functionality; the sole effect of loading it is to send the ambient cookie value to a third-party webhook capture endpoint controlled by whoever provisioned that webhook.site token. webhook.site is a generic ad-hoc data-collection service, unrelated to any legitimate publisher infrastructure.

Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.

Malicious versions

1 flagged
1.0.0

Indicators of compromise (SHA-256)

41ee1dafe6dce8750ac695c9d13e13c2808e2f35d94bbbcc41a4444a02541409
539e9def7d4d421fa2797a7c169799095f619a7408339e1c0c390b97a4f088f5

Detection & response playbook

Malicious package

  1. Find it

    Search your lockfiles and build artifacts for my-ctf-helper-script-9921 (version 1.0.0).

  2. If you installed it — respond

    Remove my-ctf-helper-script-9921 from your project and lockfile, then assume any secrets accessible to the build or runtime were exposed: rotate API keys, tokens, and credentials, and audit for unexpected outbound activity or persistence.

  3. Did it already run?

    If my-ctf-helper-script-9921 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. my-ctf-helper-script-9921 on npm has been identified as a malicious package (version 1.0.0 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-020273GHSA-7mhc-78r2-fgw8

References

Credits

  • Amazon Inspector · finder

Detect & block this

O3 blocks my-ctf-helper-script-9921-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the malicious outbound activity and severs the channel.

Malware detection Runtime egress monitoring

Explore

All malware advisories How O3 detects malware Vulnerability database
my-ctf-helper-script-9921 (npm) malicious package — MAL-2026-16365 | O3 Security