MAL-2026-17605 Malicious code in ligbtning-invoice (RubyGems)

RubyGems runs this gem's native extension script ext/ligbtning-invoice/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's native extension script extconf.rb, which RubyGems executes automatically during gem install, base64-decodes an embedded Ruby payload and evaluates it inside a double-forked, detached background process. The payload XOR-decodes a hardcoded plain-HTTP URL at 45.138.<redacted>:8092/wgkit.tar.gz, downloads the tarball to /tmp/.w1.tgz, extracts it, and executes the embedded wg_install.sh via bash, then removes traces. The payload is gated by environment fingerprinting that suppresses execution in CI, sandbox, and analysis environments: it checks CI env vars, hostnames matching firecracker/sandbox/vagrant/uvm, auto-generated usernames, analysis working-directory prefixes (/opt/rubygems, /tmp, /workspace), machine uptime, and the presence of developer artifacts (~/.ssh, ~/.gitconfig, ~/.npmrc, ~/.gem/credentials, ~/.bundle), then sleeps a randomized 20-40 minutes before firing. The shipped library is a hollow stub exposing only a trivial word list (LigbtningInvoice.words/word_at/index_of) and an empty C extension (Init_LigbtningInvoice is a no-op), while the gem name transposes letters relative to a legitimate Lightning/BOLT11 package, indicating a typosquat lure whose sole purpose is delivering the extconf.rb dropper.

The OpenSSF Package Analysis project identified 'ligbtning-invoice' @ 1.0.0 (rubygems) as malicious.

It is considered malicious because:

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