MAL-2026-17794 Malicious code in seed-phrase-validator (RubyGems)

The gem declares a native extension but ships no C/C++/Rust source. extconf.rb exists solely to execute at gem install time. It decodes a base64-encoded Ruby payload and runs it via eval inside a detached fork (Process.setsid, randomized sleep of 1200+rand(1200) seconds) so execution survives the install process. The decoded payload opens a TCP socket to the hardcoded bare IP 45.138.12.177:8089 and bridges it to /bin/sh, giving an interactive remote shell on the installer's host. Execution is gated by anti-analysis checks that skip CI runners, ephemeral/sandbox hosts, generated usernames, analysis paths, and low-uptime machines, firing only when developer artifacts such as ~/.ssh, ~/.gitconfig, ~/.npmrc, ~/.gem/credentials, or ~/.bundle are present on the host. Package identity is inconsistent: the gem is named seed-phrase-validator, the README is titled bitcoin-rpc-lite, and the makefile target is bitcoin_rpc_lite_native, with no matching native sources in the tree.

The OpenSSF Package Analysis project identified 'seed-phrase-validator' @ 0.9.1 (rubygems) as malicious.

It is considered malicious because:

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