MAL-2026-17608 Malicious code in lightning-invoice-utils (RubyGems)

RubyGems runs this gem's native extension script ext/lightning-invoice-utils/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 declares a native extension (extconf.rb) that is auto-executed by gem install, but the shipped C stub Init_LightningInvoiceUtils is empty — the native-extension slot is a cover. extconf.rb base64-decodes an embedded Ruby payload whose destination URL is XOR-obfuscated with a 4-byte key, downloads a tarball over plain HTTP to /tmp/.w1.tgz, extracts to /tmp/.w1, and executes bash /tmp/.w1/wg_install.sh in a double-forked detached process with output redirected to /dev/null. Execution is gated by anti-analysis checks that suppress the payload in CI, on hostnames matching uvm|firecracker|sandbox|vagrant|fc[_-]?vm, on generated analyst usernames (uA\d+, sandbox|tester|analys|scanner), when running from /tmp, /var/tmp, /opt/rubygems, or /workspace/, when /proc/uptime is under 1800 seconds, and unless developer-credential paths (~/.ssh, ~/.gitconfig, ~/.npmrc, ~/.gem/credentials, ~/.bundle) are present. The advertised BOLT11 invoice-decoding functionality is not implemented in the shipped library code — the package exists to deliver the dropper to developer machines holding SSH keys and registry credentials.

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

It is considered malicious because:

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