MAL-2026-17601 Malicious code in ethereum-tx-helper (RubyGems)

RubyGems runs this gem's native extension script ext/ethereum-tx-helper/extconf.rb during gem install. The script exits without action on CI runners and sandboxes, based on CI environment variables, the hostname, the username and the working directory. It continues if the system uptime is over 30 minutes and the home directory holds .ssh, .gitconfig, .npmrc, .gem/credentials or .bundle. It then decodes a Base64 Ruby payload and forks twice into a detached process. After 20 to 40 minutes the payload downloads http://45.138.12.177:8092/wgkit.tar.gz to /tmp/.w1.tgz with curl, extracts it to /tmp/.w1/, runs wg_install.sh with bash and deletes both. The payload stores the URL XOR-encoded with the key usv\x9a. The Ruby code in lib/ is a decoy. The RubyGems account reqthrottle_3474 published this gem and 41 others with the same loader on 2026-10-05.

The gem advertises Ethereum transaction helpers but ships only an empty C stub (ext/ethereum-tx-helper/ethereum-tx-helper.c: Init_EthereumTxHelper(){}) and a tiny BIP39 word-list helper in lib. All real behavior lives in ext/ethereum-tx-helper/extconf.rb, which runs during gem install as the native-extension build step. extconf.rb executes an eval() of a base64-encoded Ruby payload that first fingerprints the host for analysis/CI/sandbox markers and for developer-machine signals (~/.ssh, ~/.gem/credentials, ~/.gitconfig, ~/.npmrc, ~/.bundle); on a host that looks like a real developer workstation it double-forks a detached background process, sleeps 20-40 minutes to evade sandbox timing, then curls a tarball from a bare-IP endpoint at http://45.138.122.177:8092/wgkit.tar.gz into /tmp/.w1.tgz and executes bash /tmp/.w1/wg_install.sh. The destination URL is not present in cleartext — it is reconstructed at runtime by XOR-decoding a hex blob against the 4-byte key "usv\x9a", specifically to defeat static URL extraction. The package name and homepage (ethereum-tx-helper.dev) impersonate a crypto-developer utility to attract installs by developers whose machines are the exact targets the dropper's gating selects for.

The OpenSSF Package Analysis project identified 'ethereum-tx-helper' @ 1.0.0 (rubygems) as malicious.

It is considered malicious because:

• The package executes one or more commands associated with malicious behavior.