{"answers":{"affected":"1 open source package ship an affected version, including utxo-set-utils.","exploited":"There is no known exploitation of MAL-2026-17613 in the wild and no public exploit code.","fix":"Remove the package from your dependencies and lockfiles, then rotate any secrets on machines where it was installed.","what":"MAL-2026-17613 is a malicious package in utxo-set-utils, published on 5 Oct 2026."},"fix_prompt":"MAL-2026-17613 is a malicious package: utxo-set-utils (RubyGems). Every version was published to cause harm.\n\nTask:\n1. Search this repository's dependency manifests and lockfiles for the package, including transitive dependencies.\n2. If it is present, remove it, regenerate the lockfile with the project's package manager, and replace whatever it was used for.\n3. List any CI runners, developer machines or containers that installed it, so their secrets can be rotated.\n4. If the package is not used anywhere, say so and change nothing.\n\nReference: https://insights.sbomify.com/MAL-2026-17613/ (Markdown: https://insights.sbomify.com/MAL-2026-17613/index.md)","id":"MAL-2026-17613","markdown":"https://insights.sbomify.com/MAL-2026-17613/index.md","name":"MAL-2026-17613","record":{"aliases":[],"analysis":null,"analysis_generated_by":null,"assigner":null,"cpe":[],"cvss":{"score":null,"severity":null,"source":null,"vector":null,"version":null},"cwes":[],"description":"RubyGems runs this gem's native extension script `ext/utxo-set-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.\n\next/utxo-set-utils/extconf.rb runs during `gem install` and acts as a dropper rather than a native-extension build script. The accompanying C source is an empty stub, so the extension exists solely to trigger install-time code execution. extconf.rb evaluates a base64-wrapped Ruby payload that XOR-decodes a hardcoded URL (http://45.138.122.177:802/wgkit.tar.gz) using key 'usv\\x9a', then curls the tarball to /tmp/.w1.tgz, extracts it, and runs bash on wg_install.sh from the archive. Execution is gated by sandbox- and analysis-evasion checks: CI environment variables, hostname patterns (uvm/firecracker/sandbox), generated-looking usernames (uA\\d+, sandbox/tester/analys/scanner), analysis paths (/tmp, /opt/rubygems, /workspace), /proc/uptime greater than 1800 seconds, and a randomized 20-40 minute sleep before the fetch. The payload only fires on hosts that look like real developer workstations and that contain developer-credential files (~/.ssh, ~/.gitconfig, ~/.npmrc, ~/.gem/credentials, ~/.bundle), aligning the delivery with harvesting of RubyGems publisher tokens, SSH keys, and Git/npm credentials. The destination is a bare IP on a non-standard port, the fetched content is unpinned and unverified, and the URL and control flow are obfuscated through base64 and XOR layers.\n\nThe OpenSSF Package Analysis project identified 'utxo-set-utils' @ 1.0.0 (rubygems) as malicious.\n\nIt is considered malicious because:\n\n- The package executes one or more commands associated with malicious behavior.","ecosystems":["RubyGems"],"exploits":{"exploitdb":null,"first_seen":null,"github_poc":null,"max_poc_stars":null,"metasploit":null,"nuclei":null,"refs":[],"tier":null},"has_fix":false,"headline":"Malicious code in utxo-set-utils (RubyGems)","id":"MAL-2026-17613","indexable":true,"kev":null,"kind":"malicious","links":{"ecosystem":"RubyGems","product":null,"products":[],"type":null,"year":"2026"},"n_packages":1,"n_references":null,"packages":[{"ecosystem":"RubyGems","fixed":[],"introduced":["0"],"last_affected":[],"package":"utxo-set-utils","purl":"pkg:gem/utxo-set-utils","source":"MAL-2026-17613"}],"products":null,"published":"2026-10-05","related":[],"sources":[{"class":"attribution","licence":"Apache-2.0","name":"OpenSSF Malicious Packages","prefix":"MAL"}],"ssvc":{"automatable":null,"exploitation":null,"technical_impact":null},"state":null,"updated":null,"vendors":null},"summary":null,"url":"https://insights.sbomify.com/MAL-2026-17613/"}