{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "assemblyline-service-client"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "4.6.0.stable11"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "assemblyline-service-client"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "4.6.1.dev0"
            },
            {
              "fixed": "4.6.1.dev138"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2025-55013"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-23"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2025-07-25T14:15:48Z",
    "nvd_published_at": "2025-08-09T03:15:47Z",
    "severity": "MODERATE"
  },
  "details": "**Path-Traversal -\u003e Arbitrary File Write in Assemblyline Service Client**\n\n**IMPORTANT**: This vulnerability is valid if you decide to use the assemblyline-service-client outside of the normal practice to using Assemblyline in a production environment. In practice, this code should always be executed within a containerized environment such as [assemblyline-v4-service](https://github.com/CybercentreCanada/assemblyline-v4-service) which ensures filesystem-level permissions of what the running user is allowed to access. Furthermore, there is fewer chances for a MiTM compromise when deployed properly in a Docker or Kubernetes deployment where the platform will assign the correct network policies to secure connections between containers instead of relying on the user to set this up manually.\n\nSee https://github.com/CybercentreCanada/assemblyline/issues/382 for further discussion.\n\n---\n\n## 1. Summary  \nThe Assemblyline 4 **service client** (`task_handler.py`) accepts a SHA-256 value returned by the service **server** and uses it directly as a local file name.  \n\u003e No validation / sanitisation is performed.\n\nA **malicious or compromised server** (or any MITM that can speak to client) can return a path-traversal payload such as  \n`../../../etc/cron.d/evil`  \nand force the client to write the downloaded bytes to an arbitrary location on disk.\n\n---\n\n## 2. Affected Versions  \n| Item | Value |\n|---|---|\n| **Component** | `assemblyline-service-client` |\n| **Repository** | [CybercentreCanada/assemblyline-service-client](https://github.com/CybercentreCanada/assemblyline-service-client) |\n| **Affected** | **All releases up to master branch.**  |\n\n\n---\n\n## 3. CVSS 3.1 Vector \u0026 Score  \n```\nCVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:L\n```\n\n\n---\n\n## 4. Technical Details\n\n| Field | Content |\n|---|---|\n| **Location** | `assemblyline_service_client/task_handler.py`, inside `download_file()` |\n| **Vulnerable Line** | `file_path = os.path.join(self.tasking_dir, sha256)` |\n| **Root Cause** | The `sha256` string is taken directly from the service-server JSON response and used as a file name without any validation or sanitisation. |\n| **Exploit Flow** | 1. Attacker (service server) returns HTTP 200 for `GET /api/v1/file/../../../etc/cron.d/evil`.\u003cbr\u003e2. Client writes the response body to `/etc/cron.d/evil`.\u003cbr\u003e3. Achieves arbitrary file write (code execution if file is executable). |\n\n---\n\n## 5. Impact  \n- **Integrity** \u2013 Overwrite any file writable by the service UID (often root).  \n- **Availability** \u2013 Corrupt critical files or exhaust disk space.  \n- **Code Execution** \u2013 Drop cron jobs, systemd units, or overwrite binaries.\n\n---\n\n## 6. Mitigation / Fix\n\n```python\nimport re\n\n_SHA256_RE = re.compile(r\u0027^[0-9a-fA-F]{64}\\Z\u0027)\n\ndef download_file(self, sha256: str, sid: str) -\u003e Optional[str]:\n    if not _SHA256_RE.fullmatch(sha256):\n        self.log.error(f\"[{sid}] Invalid SHA256: {sha256}\")\n        self.status = STATUSES.ERROR_FOUND\n        return None\n    # or your preferred way to check if a string is a shasum.\n```\n---",
  "id": "GHSA-75jv-vfxf-3865",
  "modified": "2025-08-12T13:26:14Z",
  "published": "2025-07-25T14:15:48Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/CybercentreCanada/assemblyline/security/advisories/GHSA-75jv-vfxf-3865"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-55013"
    },
    {
      "type": "WEB",
      "url": "https://github.com/CybercentreCanada/assemblyline-service-client/commit/351414e7e96cc1f5640ae71ae51b939e8ba30900"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/CybercentreCanada/assemblyline-service-client"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:L",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Assemblyline 4 service client vulnerable to Arbitrary Write through path traversal in Client code "
}