Which versions of w002yardprobe are malicious?

The following RubyGems versions of w002yardprobe are flagged malicious: 0.0.4, 0.0.5. Treat any of these as compromised.

How do I remediate w002yardprobe if I installed it?

w002yardprobe 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 w002yardprobe — how do I know if it already compromised me?

If w002yardprobe 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 w002yardprobe part of a known attack campaign?

Yes — w002yardprobe is associated with the IN-MAL-2026-022534, IN-MAL-2026-022533 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 w002yardprobe across my projects, lockfiles, and CI pipelines?

Search your lockfiles and build artifacts for w002yardprobe (2 malicious versions).

Malicious package

w002yardprobeRubyGems

Advisory published Nov 4, 2026Updated Nov 4, 2026

w002yardprobe is a confirmed malicious RubyGems package (MAL-2026-18599) that steals credentials and exfiltrates sensitive data (malicious versions 0.0.4, 0.0.5). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in w002yardprobe (RubyGems)

MAL-2026-18599

Immediate action

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

gem uninstall w002yardprobe

What this malware does

The gem ships a .yardopts file containing --load./script.rb, which causes YARD to execute script.rb whenever documentation is generated for the gem (locally via yard doc, in CI, or on doc-hosting services such as RubyDoc.info). script.rb collects host identifiers — Socket.gethostname, current working directory, UID, and RUBY_VERSION — and POSTs them via Net::HTTP.post_form to the hardcoded third-party collector https://webhook.site/97fa3c6a-3fad-4d2d-8312-15dc37e41e66. The same script also rewrites lib/w002yardprobe.rb in place (substituting a MARKSLOT token with a runtime stamp) and drops sentinel files W002SCRIPT_RAN.txt and W002EGRESS_OK.txt in the detected build directory (e.g. /build), indicating the gem is instrumented to probe a documentation-build sandbox. The package self-identifies as a probe; the exfiltration and build-environment mutation are the gem's purpose. The trigger is YARD doc generation rather than gem install or require, so the harm materializes against whichever host (developer workstation, CI runner, or doc-hosting pipeline) processes the gem's documentation.

Malicious versions

2 flagged

0.0.40.0.5

Indicators of compromise (SHA-256)

5252a1d5dd27d6e0edd3c1fc3936ff09d93b2fcc8e5544afc09fe7fb7d90bee5

721580f8eda44ad5ee7604f5ba0648e8830302f784e3e4a995e02ca7359c909e

Detection & response playbook

Credential / info stealer

Find it
Search your lockfiles and build artifacts for w002yardprobe (2 malicious versions).
If you installed it — respond
w002yardprobe 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 w002yardprobe 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. w002yardprobe on RubyGems has been identified as a malicious package (versions 0.0.4, 0.0.5 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-022534IN-MAL-2026-022533

References

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks w002yardprobe-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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