{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 2.20.1"
      },
      "package": {
        "ecosystem": "Packagist",
        "name": "kimai/kimai"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.21.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [],
  "database_specific": {
    "cwe_ids": [
      "CWE-1395",
      "CWE-611"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2024-09-17T18:36:50Z",
    "nvd_published_at": null,
    "severity": "HIGH"
  },
  "details": "### Summary\nKimai uses [PHPSpreadsheet](https://github.com/PHPOffice/PhpSpreadsheet) for importing and exporting invoices. Recently, a [CVE](https://github.com/PHPOffice/PhpSpreadsheet/security/advisories/GHSA-ghg6-32f9-2jp7) was identified in PHPSpreadsheet, which could lead to an XXE vulnerability.\n\n\n### Details\n\nExploitation requires an Administrator account, allowing the upload of an `XLSX` template containing the payload. The vulnerability is triggered by the following code snippet:\n\n```php\n// https://github.com/kimai/kimai/blob/b1903ba18359be16dd32ea9c40377c486498f082/src/Invoice/Renderer/AbstractSpreadsheetRenderer.php#L41\npublic function render(InvoiceDocument $document, InvoiceModel $model): Response\n{\n    $spreadsheet = IOFactory::load($document-\u003egetFilename());\n    $worksheet = $spreadsheet-\u003egetActiveSheet();\n    $entries = $model-\u003egetCalculator()-\u003egetEntries();\n    $sheetReplacer = $model-\u003etoArray();\n    $invoiceItemCount = \\count($entries);\n    if ($invoiceItemCount \u003e 1) {\n        $this-\u003eaddTemplateRows($worksheet, $invoiceItemCount);\n    }\n}\n```\n\nThe `IOFactory::load` function utilizes `simplexml_load_string`, which has previously been demonstrated to be vulnerable to XXE attacks.\n\nWhile this is not directly an XXE in Kimai, it does however impact the latest stable version.\n\n \n### PoC\n\nBy uploading a malicious `XLSX` template, the payload will be triggered every time an invoice is generated.\n\n```xml\n\u003c?xml version=\"1.0\" encoding=\u0027UTF-7\u0027 standalone=\"yes\"?\u003e\n+ADw-!DOCTYPE foo [ \u003c!ENTITY % xxe SYSTEM \"php://filter/.......\" \u003e %xxe;]\u003e.....\n```\n\nFor a better a visibility, I will upload both a:\n- Malicious template sample for testing \n- An exported invoice, showing the contents of target file during the export. \n\n### Impact\nLocal File Read / RCE in edge cases where `phar://` can be utilized with [gadget chains](https://github.com/ambionics/phpggc) . \n\n\n[export.xlsx](https://github.com/user-attachments/files/16803913/export.xlsx)\n[sample_template.xlsx](https://github.com/user-attachments/files/16803916/sample_template.xlsx)\n",
  "id": "GHSA-534c-hcr7-67jg",
  "modified": "2024-11-14T17:45:16Z",
  "published": "2024-09-17T18:36:50Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/PHPOffice/PhpSpreadsheet/security/advisories/GHSA-ghg6-32f9-2jp7"
    },
    {
      "type": "WEB",
      "url": "https://github.com/kimai/kimai/security/advisories/GHSA-534c-hcr7-67jg"
    },
    {
      "type": "WEB",
      "url": "https://github.com/kimai/kimai/commit/3204dcb03e1003dba90178667a4667ce3edb87b5"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/kimai/kimai"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Kimai has an XXE Leading to Local File Read"
}