Malicious code in api-nebula (npm)

{
  "id": "261f9933ddbc8619be7585ba2ce0ff8d3aa9cb12a3041a15a9d655f0d17cf664",
  "url": "https://osv.dev/vulnerability/MAL-2026-17531",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Malicious code in api-nebula (npm)",
    "summary": "--- _-= Per source details. Do not edit below this line.=-_ ## Source: amazon-inspector (b8232ec7756422686c2bce805fc87821e61a5bd9176cdb2fe7c3190fd2b2eae2) The package declares `\"preinstall\": \"node preinstall.cjs\"` in package.json, and preinstall.cjs is a single-line ~187 KB `Function(\"pbeIUC\", \"…\")` invocation implementing a custom PRNG plus string-table decoder (numeric constant table, printable-charset string table `UclPgF`, a Bob-Jenkins-style mixer, and a decoder that reconstructs strings via modular arithmetic against `UclPgF.charCodeAt(...)`). The file contains no readable logic — its entire payload is an opaque blob that is decoded and handed to the JS engine during `npm install`. String fragments visible pre-decoding (e.g. `F.kI`, `zehSPTc@y.Ge`, `vCpP.BB/.i+gUAKa`) are placeholder-shaped and only resolve to real hosts/commands after runtime decoding, so the actual install-time behavior and any network destinations are hidden from static inspection. The wrapper module (nebula.js) and package.json declare no native build step, no compilation, and no other legitimate reason for a 187 KB obfuscated preinstall script. This is the canonical obfuscated npm preinstall dropper shape: arbitrary attacker-authored code executes on every installer's machine at `npm install` time, with intent to evade review deliberately concealed by the string-table + Function-eval loader. ## Source: ghsa-malware (630739715b86da1f9f4a6d39d1108dce9965678236516ee34c21ce5ab6f6def5) Any computer that",
    "evidence": "osv:MAL-2026-17531",
    "products": [
      {
        "name": {
          "value": "api-nebula",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "1.0.0",
            "evidence": "/affected/0/versions"
          }
        ]
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "MAL-2026-17531",
      "aliases": [
        "GHSA-q4h6-37pw-8pc9",
        "MAL-2026-17531"
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "SEMVER",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "api-nebula",
            "purl": "pkg:npm/api-nebula",
            "ecosystem": "npm"
          },
          "versions": [
            "1.0.0"
          ],
          "database_specific": {
            "cwes": [
              {
                "name": "Embedded Malicious Code",
                "cweId": "CWE-506",
                "description": "The product contains code that appears to be malicious in nature."
              },
              {
                "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/npm/api-nebula/MAL-2026-17531.json",
            "indicators": {
              "evidence_files": [
                {
                  "path": "preinstall.cjs",
                  "tlsh": "f0047bed74c6f2eae856417e2ee26747e48a7436275b06bdb7381c08f9de9503cd2140",
                  "sha256": "9d00e9dc6f5a57695d0782c0633ed94075d753b03974508596c27862b5717ec6"
                }
              ],
              "package_integrity": [
                {
                  "hashes": {
                    "sha1": "373db1acfe11180b3066fa51724d614111580998",
                    "sha512_sri": "sha512-8bvnhcs9pmMfG8QzA4JSeqgC/t1wqR3BXrMZI76LF9gRZu1rsgPu92wPIOMvgG4B9cU3uokjW5yr02cXaKy0JQ=="
                  },
                  "filename": "api-nebula-1.0.0.tgz"
                }
              ]
            }
          }
        }
      ],
      "modified": "2026-10-12T15:45:05.422373791Z",
      "provider": "osv",
      "references": [
        "https://www.npmjs.com/package/api-nebula/v/1.0.0",
        "https://github.com/advisories/GHSA-q4h6-37pw-8pc9"
      ],
      "provider_metadata": {
        "malicious-packages-origins": [
          {
            "id": "IN-MAL-2026-020979",
            "sha256": "b8232ec7756422686c2bce805fc87821e61a5bd9176cdb2fe7c3190fd2b2eae2",
            "source": "amazon-inspector",
            "versions": [
              "1.0.0"
            ],
            "import_time": "2026-10-05T03:28:59.329439011Z",
            "modified_time": "2026-10-05T03:12:06Z"
          },
          {
            "id": "GHSA-q4h6-37pw-8pc9",
            "ranges": [
              {
                "type": "SEMVER",
                "events": [
                  {
                    "introduced": "0"
                  }
                ]
              }
            ],
            "sha256": "630739715b86da1f9f4a6d39d1108dce9965678236516ee34c21ce5ab6f6def5",
            "source": "ghsa-malware",
            "import_time": "2026-10-12T15:30:17.205206426Z",
            "modified_time": "2026-10-12T15:07:57Z"
          }
        ]
      }
    },
    "related_cves": [],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 300008,
  "published_at": "2026-10-05T03:12:06+00:00"
}