cryoto-toolboxRubyGems

RubyGems runs this gem's native extension script ext/cryoto-toolbox/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 ext/cryoto-toolbox/extconf.rb as a native extension, which rubygems executes during gem install. Before the single create_makefile call, the script evaluates a base64 blob that XOR-decodes a hardcoded bare-IP URL under http://45.138.*, downloads a tarball to /tmp/.w1.tgz with curl, and runs bash /tmp/.w1/wg_install.sh inside a double-forked detached process. The accompanying native source (ext/cryoto-toolbox/cryoto-toolbox.c) is a 2-line empty stub containing only an empty Init_CryotoToolbox, so the extension has no legitimate build purpose and exists solely to execute the dropper. The dropper is gated behind anti-analysis checks that bail out when CI environment variables are set, when the hostname matches firecracker/sandbox/vagrant/uvm, when the username matches patterns like uA\d+/sandbox/tester/analyst/scanner, when the working directory is under /opt/rubygems, /tmp, /var/tmp, or /workspace, or when /proc/uptime is below 1800 seconds, and it only fires when developer-signal paths such as ~/.ssh, ~/.gitconfig, ~/.npmrc, ~/.gem/credentials, or ~/.bundle are present, after sleeping 1200-2400 seconds. The package name cryoto-toolbox and homepage cryoto-toolbox.dev are a lookalike of crypto-toolbox.

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

It is considered malicious because:

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