Which versions of u2f_client are malicious?

The following RubyGems versions of u2f_client are flagged malicious: 0.2. Treat any of these as compromised.

How do I remediate u2f_client if I installed it?

Remove u2f_client 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 u2f_client — how do I know if it already compromised me?

If u2f_client 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 u2f_client part of a known attack campaign?

Yes — u2f_client is associated with the RLMA-2025-06635, RLUA-2026-09612 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 u2f_client across my projects, lockfiles, and CI pipelines?

Search your lockfiles and build artifacts for u2f_client (version 0.2).

Malicious package

u2f_clientRubyGems

Advisory published Dec 23, 2025Updated Sep 24, 2026

u2f_client is a confirmed malicious RubyGems package (MAL-2025-192924) that executes malicious code on install (malicious version 0.2). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in u2f_client (RubyGems)

MAL-2025-192924

Immediate action

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

gem uninstall u2f_client

Malicious versions

1 flagged

0.2

Indicators of compromise (SHA-256)

de3b4548370b98544c7657bc55fc532d9f59805f7d81fa554bd01d118225f372

0751a96fc52e7dfb1bf8eef859c0ecad0bd4e9c1a4e8fe337daa53440c8d1643

Detection & response playbook

Malicious package

Find it
Search your lockfiles and build artifacts for u2f_client (version 0.2).
If you installed it — respond
Remove u2f_client 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 u2f_client 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. u2f_client on RubyGems has been identified as a malicious package (version 0.2 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

RLMA-2025-06635RLUA-2026-09612

References

github.com

Credits

ReversingLabs · finder

Detect & block this

O3 blocks u2f_client-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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