{
  "affected": [
    {
      "database_specific": {
        "cwes": [
          {
            "cweId": "CWE-506",
            "description": "The product contains code that appears to be malicious in nature.",
            "name": "Embedded Malicious Code"
          }
        ],
        "indicators": {
          "evidence_files": [
            {
              "path": "ext/evm_tx_decoder/extconf.rb",
              "sha256": "10218e975f54a4f11fe3954e1b584a5f05054003bf5773c3c2b8cceaa74ba763",
              "tlsh": "9751775acf8359e55aa1c0c045798012faa3ab0a50646875f3ee0868ff59b26c0f12fe"
            },
            {
              "path": "lib/evm_tx_decoder.rb",
              "sha256": "2a64978f5ee8393abbf5da13fd56f43f9134390b2fdda5912d374f4420f69939",
              "tlsh": "c7d0979d433e3820803e4421a4eceec79fe8203243501024a92d52c5461323e233be71"
            }
          ]
        },
        "source": "https://github.com/ossf/malicious-packages/blob/main/osv/malicious/rubygems/evm-tx-decoder/MAL-2026-17787.json"
      },
      "package": {
        "ecosystem": "RubyGems",
        "name": "evm-tx-decoder",
        "purl": "pkg:gem/evm-tx-decoder"
      },
      "versions": [
        "0.9.1"
      ]
    }
  ],
  "credits": [
    {
      "contact": [
        "inspector-research@amazon.com"
      ],
      "name": "Amazon Inspector",
      "type": "FINDER"
    },
    {
      "contact": [
        "https://github.com/ossf/package-analysis",
        "https://openssf.slack.com/channels/package_analysis"
      ],
      "name": "OpenSSF: Package Analysis",
      "type": "FINDER"
    }
  ],
  "database_specific": {
    "malicious-packages-origins": [
      {
        "id": "IN-MAL-2026-021359",
        "import_time": "2026-10-11T14:17:59.127383923Z",
        "modified_time": "2026-10-11T13:47:20Z",
        "sha256": "e478aa0270779720106fc6169e89fde089af352214fc720fbf8c284d51415f59",
        "source": "amazon-inspector",
        "versions": [
          "0.9.1"
        ]
      },
      {
        "import_time": "2026-10-13T23:14:38.643324133Z",
        "modified_time": "2026-10-11T07:35:27Z",
        "sha256": "9cdd1c9ff14337d1c7476955b739c100c55ce370cdcaf28eecb2cbb1e7c32cc4",
        "source": "ossf-package-analysis",
        "versions": [
          "0.9.1"
        ]
      }
    ]
  },
  "details": "\n---\n_-= Per source details. Do not edit below this line.=-_\n\n## Source: amazon-inspector (e478aa0270779720106fc6169e89fde089af352214fc720fbf8c284d51415f59)\nThe 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.\n\n## Source: ossf-package-analysis (9cdd1c9ff14337d1c7476955b739c100c55ce370cdcaf28eecb2cbb1e7c32cc4)\nThe OpenSSF Package Analysis project identified 'evm-tx-decoder' @ 0.9.1 (rubygems) as malicious.\n\nIt is considered malicious because:\n\n- The package executes one or more commands associated with malicious behavior.\n",
  "id": "MAL-2026-17787",
  "modified": "2026-10-13T23:30:06.280113714Z",
  "published": "2026-10-11T07:35:27Z",
  "references": [
    {
      "type": "PACKAGE",
      "url": "https://rubygems.org/gems/evm-tx-decoder/versions/0.9.1"
    }
  ],
  "schema_version": "1.9.0",
  "summary": "Malicious code in evm-tx-decoder (RubyGems)"
}