# MAL-2026-17585: Malicious code in bitcoij-ruby (RubyGems)


- **Type:** Malicious package
- **Package:** `bitcoij-ruby` (RubyGems)
- **Published:** 5 Oct 2026

## What is MAL-2026-17585?

MAL-2026-17585 is a malicious package in bitcoij-ruby, published on 5 Oct 2026. 

### Official description

RubyGems runs this gem's native extension script `ext/bitcoij-ruby/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 (ext/bitcoij-ruby/extconf.rb) whose matching C source is an empty 50-byte Init function, so the extension exists solely to run extconf.rb during `gem install`. extconf.rb base64-decodes a Ruby snippet and eval()s it inside a double-forked, detached child. The decoded payload reconstructs a hardcoded C2 URL via XOR-obfuscated hex bytes resolving to http://45.138.129.177:8092/wgkit.tar.gz, downloads the archive to /tmp over plain HTTP with no integrity check, extracts it, and executes bash /tmp/.w1/wg_install.sh on the installer's machine. Execution is gated by sandbox/analysis evasion checks that skip CI environments, ephemeral hostnames (firecracker/sandbox/vagrant), generated usernames, analysis cwd prefixes (/tmp, /var/tmp, /opt/rubygems, /workspace), hosts with uptime under 1800 seconds, and hosts lacking developer-credential paths (~/.ssh, ~/.gitconfig, ~/.gem/credentials, ~/.bundle, ~/.npmrc); it also sleeps 1200+rand(1200) seconds before firing. The gem is advertised as a pure-Ruby Bitcoin/BIP-39 helper with no legitimate reason to probe developer credential stores or fetch remote shell scripts.

## What should I do about MAL-2026-17585?

Remove the package from your dependencies and lockfiles, then rotate any secrets on machines where it was installed.

## Fix prompt for AI coding agents

```text
MAL-2026-17585 is a malicious package: bitcoij-ruby (RubyGems). Every version was published to cause harm.

Task:
1. Search this repository's dependency manifests and lockfiles for the package, including transitive dependencies.
2. If it is present, remove it, regenerate the lockfile with the project's package manager, and replace whatever it was used for.
3. List any CI runners, developer machines or containers that installed it, so their secrets can be rotated.
4. If the package is not used anywhere, say so and change nothing.

Reference: https://insights.sbomify.com/MAL-2026-17585/ (Markdown: https://insights.sbomify.com/MAL-2026-17585/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-17585

---
From sbomify Insights: https://insights.sbomify.com/MAL-2026-17585/
Summaries are generated and may contain mistakes; the official description above is the record.