tx-broadcast-utils

GHSA-m56c-f68h-prj5

Malicious code in tx-broadcast-utils (RubyGems)

Details

**Severity:** Critical

**Affected versions:** `= 1.0.0`

## Source: amazon-inspector (60efdf159c3ce8550c985b3f19cbe72f2bfcae0266cb63fb8c0dd458b56b9901)
The gem's native-extension script (ext/.../extconf.rb) embeds a base64-encoded Ruby payload that is eval'd at `gem install` time. The payload double-forks and detaches a background process which sleeps 20-40 minutes, reconstructs a C2 URL by XOR-decoding a hex blob to http://45.138.17.70:809/wgkit.tar.gz, downloads the tarball to /tmp/.w1.tgz, extracts it to /tmp/.w1, and executes wg_install.sh as the installing user. Execution is gated on anti-analysis checks that suppress the payload in CI, ephemeral/sandbox hostnames, generated usernames matching /uA\d+/, paths under /tmp or /opt/rubygems, and hosts with short uptime, and requires developer-machine signals such as ~/.ssh, ~/.gitconfig, and ~/.gem/credentials before firing. The advertised purpose (Bitcoin transaction broadcast helpers over public esplora endpoints) is a decoy: the shipped library only exposes a truncated BIP39 word list with no broadcast code, and the native extension's C source is an empty Init_ stub. The extconf.rb dropper is the gem's only functional component.

---

Credit: [OpenSSF](https://github.com/ossf/malicious-packages) ([source](https://github.com/ossf/malicious-packages/blob/a00eadccb320bc1163c7d818541ccc8206217cce/osv/malicious/rubygems/tx-broadcast-utils/MAL-2026-17612.json))

**References:**
- https://github.com/ossf/malicious-packages/blob/a00eadccb320bc1163c7d818541ccc8206217cce/osv/malicious/rubygems/tx-broadcast-utils/MAL-2026-17612.json
- https://rubygems.org/gems/tx-broadcast-utils/versions/1.0.0
- https://github.com/ossf/malicious-packages/blob/68375bfc9669351706a5a45c5039509f189d8e09/osv/malicious/rubygems/tx-broadcast-utils/MAL-2026-17612.json
- https://safedep.io/rubygems-crypto-gems-install-time-reverse-shell
- https://github.com/advisories/GHSA-m56c-f68h-prj5

Compromised versions (1)

= 1.0.0

Any computer that installed or ran a compromised version should be considered fully compromised. Rotate every secret on that machine from a clean environment.