bitcoin-rpc-liteRubyGems

RubyGems runs this gem's native extension script ext/req_throttle_mini/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, forks twice into a detached process, waits 20 to 40 minutes and opens a reverse shell that connects /bin/sh to 45.138.12.177 on TCP port 8089. The shell reconnects every 30 seconds. 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's native-extension build script extconf.rb, which runs automatically during gem install, contains a base64-encoded Ruby payload that is decoded and passed to eval inside a double-forked, detached child process. The decoded payload opens a TCP socket to the hardcoded attacker-controlled endpoint 45.138.12.177:8089 and bridges it to /bin/sh in a reconnect loop, giving the operator of that endpoint an interactive shell on the installing host. Execution is gated by evasion checks: the script refuses to run when environment variables or hostnames indicate CI (CI, GITHUB_ACTIONS, TRAVIS, JENKINS_URL, GITLAB_CI, CODESPACES; hostnames matching uvm/firecracker/sandbox/vagrant; usernames matching uA\d+/sandbox/tester/analys/scanner; cwd under /tmp, /opt/rubygems, /workspace; /proc/uptime under 1800 seconds) and fires only when developer-presence markers are found on disk (~/.ssh, ~/.gitconfig, ~/.npmrc, ~/.gem/credentials, ~/.bundle). The child additionally sleeps roughly 20-40 minutes before activating the shell, further hiding the behavior from short-lived analysis environments. Base64 encoding of the payload serves no functional purpose other than concealing the attacker IP, port, and /bin/sh bridge from casual source review.

The OpenSSF Package Analysis project identified 'bitcoin-rpc-lite' @ 1.0.0 (rubygems) as malicious.

It is considered malicious because:

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