CVE-2024-21496: caddy-security XSS — Exploit

Description

All versions of the package github.com/greenpau/caddy-security are vulnerable to Cross-site Scripting (XSS) via the Referer header, due to improper input sanitization. Although the Referer header is sanitized by escaping some characters that can allow XSS (e.g., [&], [<], [>], ["], [']), it does not account for the attack based on the JavaScript URL scheme (e.g., javascript:alert(document.domain)// payload). Exploiting this vulnerability may not be trivial, but it could lead to the execution of malicious scripts in the context of the target user’s browser, compromising user sessions.

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CVSS v3.1 Score

6.1

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Weakness Type (CWE)

CWE-79 Cross-site Scripting (XSS)

Affected Products

Vendor	Product	Versions
authcrunch	caddy-security	All

References

Exploits

https://blog.trailofbits.com/2023/09/18/security-flaws-in-an-sso-plugin-for-caddy/ https://github.com/greenpau/caddy-security/issues/267 https://blog.trailofbits.com/2023/09/18/security-flaws-in-an-sso-plugin-for-caddy/ https://github.com/greenpau/caddy-security/issues/267

Other References

https://security.snyk.io/vuln/SNYK-GOLANG-GITHUBCOMGREENPAUCADDYSECURITY-6249860 https://security.snyk.io/vuln/SNYK-GOLANG-GITHUBCOMGREENPAUCADDYSECURITY-6249860

Frequently Asked Questions

What is CVE-2024-21496? +

All versions of the package github.com/greenpau/caddy-security are vulnerable to Cross-site Scripting (XSS) via the Referer header, due to improper input sanitization. Although the Referer header is sanitized by escaping some characters that can allow XSS (e.g., [&], [<], [>], ["], [']), it does not account for the attack based on the JavaScript URL scheme (e.g., javascript:alert(document.domain)// payload). Exploiting this vulnerability may not be trivial, but it could lead to the execution of malicious scripts in the context of the target user’s browser, compromising user sessions. It has a CVSS v3.1 base score of 6.1 (MEDIUM).

How severe is CVE-2024-21496? +

CVE-2024-21496 has a CVSS v3.1 score of 6.1 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2024-21496? +

CVE-2024-21496 affects products from authcrunch, specifically: caddy-security. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2024-21496? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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CVE-2024-21496