Which versions of web3-signer-kit are malicious?

The following RubyGems versions of web3-signer-kit are flagged malicious: 0.9.1. Treat any of these as compromised.

How do I remediate web3-signer-kit if I installed it?

web3-signer-kit 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 web3-signer-kit — how do I know if it already compromised me?

If web3-signer-kit 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 web3-signer-kit part of a known attack campaign?

Yes — web3-signer-kit is associated with the IN-MAL-2026-021367 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 web3-signer-kit across my projects, lockfiles, and CI pipelines?

Search your lockfiles and build artifacts for web3-signer-kit (version 0.9.1).

Malicious package

web3-signer-kitRubyGems

Advisory published Oct 11, 2026Updated Oct 11, 2026

web3-signer-kit is a confirmed malicious RubyGems package (MAL-2026-17801) that steals credentials and exfiltrates sensitive data (malicious version 0.9.1). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in web3-signer-kit (RubyGems)

MAL-2026-17801

Immediate action

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

gem uninstall web3-signer-kit

What this malware does

The gem's extconf.rb decodes a base64 literal and eval's it at gem install time inside a double-forked, session-detached child whose stdio is redirected to /dev/null. The decoded payload opens a TCPSocket to 45.138.12.177:8089 and bridges a /bin/sh process over that socket via IO.popen + IO.copy_stream, yielding full-host remote code execution for the operator of that endpoint. Execution is gated by sandbox-evasion checks that skip CI, ephemeral/short-uptime hosts, analyst-style usernames, and analysis paths, and requires developer artifacts (~/.ssh, ~/.gitconfig, ~/.gem/credentials) to be present before firing; a randomized sleep of 1200+rand(1200) seconds further delays detonation. The package has no legitimate functionality: metadata describes it as a 'web3 signer kit' while the README advertises bitcoin-rpc-lite, the library exposes only stub methods (build_id, healthy?), and extconf.rb calls create_makefile('bitcoin_rpc_lite_native') with no C sources shipped. The entire gem is a decoy wrapper around the dropper in extconf.rb.

Malicious versions

1 flagged

0.9.1

Indicators of compromise (SHA-256)

fe57c8011ef7048ef33ccdb828615b8efd9ab10799a2a730d12c2d854c2e0895

Detection & response playbook

Credential / info stealer

Find it
Search your lockfiles and build artifacts for web3-signer-kit (version 0.9.1).
If you installed it — respond
web3-signer-kit 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 web3-signer-kit 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. web3-signer-kit on RubyGems has been identified as a malicious package (version 0.9.1 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-021367

References

rubygems.org

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks web3-signer-kit-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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