Denial of service in Squid

1) Uncontrolled Recursion

EUVDB-ID: #VU84442

Risk: Medium

CVSSv3.1: 6.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2023-50269

CWE-ID: CWE-674 - Uncontrolled Recursion

Exploit availability: No

Description

The vulnerability allows a remote client to perform a denial of service (DoS) attack.

The vulnerability exists due to uncontrolled recursion when parsing HTTP requests. A remote client can send a specially crafted HTTP request with the a large X-Forwarded-For header, when the follow_x_forwarded_for feature is configured, and perform a denial of service (DoS) attack.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Squid: 2.6 - 6.5

External links

http://github.com/squid-cache/squid/security/advisories/GHSA-wgq4-4cfg-c4x3
http://www.squid-cache.org/Versions/v5/SQUID-2023_10.patch
http://www.squid-cache.org/Versions/v6/SQUID-2023_10.patch

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to send a specially crafted request to the affected application in order to exploit this vulnerability.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.