Malicious code in crypto-tax-export (RubyGems)

{
  "id": "62829267d7f8dc393b705354076965b5603f829953ba7c65b1a1995a625a1416",
  "url": "https://osv.dev/vulnerability/MAL-2026-17782",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Malicious code in crypto-tax-export (RubyGems)",
    "summary": "--- _-= Per source details. Do not edit below this line.=-_ ## Source: amazon-inspector (d2481974cbcc361b29455129afea878124dafde18097efca0a87235df57f3bea) The gem's native-extension build script ext/crypto_tax_export/extconf.rb runs during `gem install`. Before executing its payload it performs sandbox/analysis-evasion checks (CI environment variables, ephemeral/generated hostnames and usernames, known analysis paths, system uptime under 30 minutes, and presence of developer-signal files such as ~/.ssh, ~/.gem/credentials, and ~/.gitconfig). When those checks indicate a real developer workstation, it double-forks a detached, stdio-closed daemon that sleeps a randomized 20-40 minutes and then executes `eval(Base64.decode64(...))` on an embedded payload that opens a /bin/sh reverse shell via TCPSocket to the hardcoded bare IP 45.138.12.177:8089 in a reconnect loop. The create_makefile call is a stub targeting an unrelated name (`bitcoin_rpc_lite_native`), the shipped lib/crypto_tax_export.rb contains only trivial VERSION/build_id/healthy? methods with no tax-export functionality, and the README is for a different package (`bitcoin-rpc-lite`), indicating the extension script is the gem's sole purpose and the advertised identity is cover.",
    "evidence": "osv:MAL-2026-17782",
    "products": [
      {
        "name": {
          "value": "crypto-tax-export",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "0.9.1",
            "evidence": "/affected/0/versions"
          }
        ]
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "MAL-2026-17782",
      "aliases": [
        "MAL-2026-17782"
      ],
      "affected": [
        {
          "package": {
            "name": "crypto-tax-export",
            "purl": "pkg:gem/crypto-tax-export",
            "ecosystem": "RubyGems"
          },
          "versions": [
            "0.9.1"
          ],
          "database_specific": {
            "cwes": [
              {
                "name": "Embedded Malicious Code",
                "cweId": "CWE-506",
                "description": "The product contains code that appears to be malicious in nature."
              }
            ],
            "source": "https://github.com/ossf/malicious-packages/blob/main/osv/malicious/rubygems/crypto-tax-export/MAL-2026-17782.json",
            "indicators": {
              "evidence_files": [
                {
                  "path": "ext/crypto_tax_export/extconf.rb",
                  "tlsh": "9751775acf8359e55aa1c0c045798012faa3ab0a50646875f3ee0868ff59b26c0f12fe",
                  "sha256": "10218e975f54a4f11fe3954e1b584a5f05054003bf5773c3c2b8cceaa74ba763"
                },
                {
                  "path": "README.md",
                  "tlsh": "b2c02b409c10f00783b09561bbc0019ba800c0cc9000c30b4874063cc0988518e65419",
                  "sha256": "c11ea90465c14afe868c0d0028b54d69fbad390a73ddb7779e88becd2957d8f3"
                }
              ]
            }
          }
        }
      ],
      "modified": "2026-10-11T14:30:07.619574367Z",
      "provider": "osv",
      "references": [
        "https://rubygems.org/gems/crypto-tax-export/versions/0.9.1"
      ],
      "provider_metadata": {
        "malicious-packages-origins": [
          {
            "id": "IN-MAL-2026-021361",
            "sha256": "d2481974cbcc361b29455129afea878124dafde18097efca0a87235df57f3bea",
            "source": "amazon-inspector",
            "versions": [
              "0.9.1"
            ],
            "import_time": "2026-10-11T14:17:59.293128453Z",
            "modified_time": "2026-10-11T13:47:41Z"
          }
        ]
      }
    },
    "related_cves": [],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 286044,
  "published_at": "2026-10-11T13:47:41+00:00"
}