# MAL-2026-17780: Malicious code in block-explorer-api (RubyGems)


- **Type:** Malicious package
- **Package:** `block-explorer-api` (RubyGems)
- **Published:** 11 Oct 2026

## What is MAL-2026-17780?

MAL-2026-17780 is a malicious package in block-explorer-api, published on 11 Oct 2026. 

### Official description

The gem's native-extension build script (extconf.rb) decodes a base64-encoded Ruby payload and passes it to eval() inside a double-forked, detached child process with stdio redirected to /dev/null. The decoded payload opens a TCP connection to the hardcoded bare-IP C2 45.138.12.177:8089 and bridges it to /bin/sh via IO.popen and IO.copy_stream in both directions, yielding a full interactive reverse shell on the installer's host under the installing user. Execution is gated by anti-analysis checks that skip CI runners, ephemeral/sandbox hostnames (uvm, firecracker, sandbox, vagrant), generated analyst usernames (uA\d+, sandbox, tester, analys, scanner), common analysis working paths (/opt/rubygems, /tmp, /var/tmp, /workspace), and hosts with uptime under 1800 seconds, firing only when developer-signal files such as ~/.ssh, ~/.gem/credentials, ~/.gitconfig, or ~/.npmrc are present, and after a randomized 20-40 minute delay. The shipped library at lib/block_explorer_api.rb is an inert 10-line stub (VERSION, build_id, healthy?) and the gemspec name (block-explorer-api, authored by generic 'block maintainers') does not match the README, which describes the package as 'bitcoin-rpc-lite'; the install hook contains the entire functional payload while the advertised library does nothing.

The OpenSSF Package Analysis project identified 'block-explorer-api' @ 0.9.1 (rubygems) as malicious.

It is considered malicious because:

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

## What should I do about MAL-2026-17780?

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-2026-17780 is a malicious package: block-explorer-api (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-2026-17780/ (Markdown: https://insights.sbomify.com/MAL-2026-17780/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-17780

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-17780/
Summaries are generated and may contain mistakes; the official description above is the record.