Which versions of swc421 are malicious?

The following RubyGems versions of swc421 are flagged malicious: 0.0.1. Treat any of these as compromised.

How do I remediate swc421 if I installed it?

Remove swc421 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.

I already installed swc421 — how do I know if it already compromised me?

If swc421 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.

Is swc421 part of a known attack campaign?

Yes — swc421 is associated with the RLMA-2026-03567, RLUA-2026-09480 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 swc421 across my projects, lockfiles, and CI pipelines?

Search your lockfiles and build artifacts for swc421 (version 0.0.1).

Malicious package

swc421RubyGems

Advisory published Jul 7, 2026Updated Sep 24, 2026

swc421 is a confirmed malicious RubyGems package (MAL-2026-8916) that executes malicious code on install (malicious version 0.0.1). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in swc421 (RubyGems)

MAL-2026-8916

Immediate action

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

gem uninstall swc421

Malicious versions

1 flagged

0.0.1

Indicators of compromise (SHA-256)

ae192f01009674aad04cbed9dbcd30f5b0d822ec11c9c51c18ffc4f75a1fa134

245afe49657d63252b44521acb1b7c6b28a2d32cfdd51b8c64aeee1deaa59d01

Detection & response playbook

Malicious package

Find it
Search your lockfiles and build artifacts for swc421 (version 0.0.1).
If you installed it — respond
Remove swc421 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.
Did it already run?
If swc421 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. swc421 on RubyGems has been identified as a malicious package (version 0.0.1 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

RLMA-2026-03567RLUA-2026-09480

References

github.com

Credits

ReversingLabs · finder

Detect & block this

O3 blocks swc421-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

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