{"answers":{"affected":"1 open source package ship an affected version, including base58-check-helper.","exploited":"There is no known exploitation of MAL-2026-17580 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-2026-17580 is a malicious package in base58-check-helper, published on 5 Oct 2026."},"fix_prompt":"MAL-2026-17580 is a malicious package: base58-check-helper (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-2026-17580/ (Markdown: https://insights.sbomify.com/MAL-2026-17580/index.md)","id":"MAL-2026-17580","markdown":"https://insights.sbomify.com/MAL-2026-17580/index.md","name":"MAL-2026-17580","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/base58-check-helper/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\nThe gem's ext/base58-check-helper/extconf.rb runs during `gem install` and, before invoking create_makefile, performs anti-analysis gating: it skips execution when CI environment variables are present, when the hostname looks ephemeral, when the username looks synthetic, when the working path matches /tmp, /opt/rubygems, or /workspace, when machine uptime is under 1800 seconds, or when common developer dotfiles are absent. When those checks indicate a real developer workstation (presence of ~/.ssh, ~/.gitconfig, ~/.npmrc, ~/.gem/credentials, or ~/.bundle), it base64-decodes an embedded Ruby payload and eval's it inside a double-forked, Process.setsid-daemonized child. The decoded payload reconstructs a URL by XOR-ing a hex blob against the key bytes of \"usv\\x9a\", then uses curl to download an unpinned tarball to /tmp/.w1.tgz, extracts it to /tmp/.w1, and executes bash /tmp/.w1/wg_install.sh. The native source accompanying the extension is a two-line empty stub, so the extension exists solely as a vehicle for the dropper. The combination of base64+XOR obfuscation, hidden /tmp staging, developer-machine targeting, sandbox/CI evasion, and daemonized execution of remote shell content is a credential-stealer dropper fingerprint.\n\nThe OpenSSF Package Analysis project identified 'base58-check-helper' @ 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 base58-check-helper (RubyGems)","id":"MAL-2026-17580","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":"base58-check-helper","purl":"pkg:gem/base58-check-helper","source":"MAL-2026-17580"}],"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-2026-17580/"}