# MAL-2026-17787: Malicious code in evm-tx-decoder (RubyGems)


- **Type:** Malicious package
- **Package:** `evm-tx-decoder` (RubyGems)
- **Published:** 11 Oct 2026

## What is MAL-2026-17787?

MAL-2026-17787 is a malicious package in evm-tx-decoder, published on 11 Oct 2026. 

### Official description

The gem's native-extension build script ext/extconf.rb decodes a base64-embedded Ruby payload and executes it via eval inside a double-forked, detached child (Process.setsid, Process.detach). The payload opens a TCPSocket to the hardcoded bare-IP C2 at 45.138.12.177:8089 and connects it bidirectionally to /bin/sh via IO.popen and IO.copy_stream, yielding an interactive remote shell on the installer host at `gem install` time. Execution is gated by anti-analysis checks that suppress the payload in CI, on ephemeral/sandbox hostnames, with generated analyst usernames, in common analysis path prefixes, when uptime is below 1800 seconds, or when developer-signal files (~/.ssh, ~/.gitconfig, ~/.npmrc, ~/.gem/credentials, ~/.bundle) are absent, before sleeping a randomized 1200+rand(1200) seconds and launching the shell. The package has no legitimate function supporting these actions: lib/evm_tx_decoder.rb is a 243-byte stub returning 'ok'/true, the README text references an unrelated `bitcoin_rpc_lite` project, and extconf.rb calls create_makefile('bitcoin_rpc_lite_native') while shipping no C/C++ sources, so the native-build pretext is a cover story for the install-time backdoor.

The OpenSSF Package Analysis project identified 'evm-tx-decoder' @ 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-2026-17787?

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-2026-17787 is a malicious package: evm-tx-decoder (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-2026-17787/ (Markdown: https://insights.sbomify.com/MAL-2026-17787/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-17787

---
From sbomify Insights: https://insights.sbomify.com/MAL-2026-17787/
Summaries are generated and may contain mistakes; the official description above is the record.