Multiple vulnerabilities in Squid

Published: 2021-10-04

Risk	Medium
Patch available	YES
Number of vulnerabilities	2
CVE-ID	CVE-2021-41611 CVE-2021-28116
CWE-ID	CWE-295 CWE-125
Exploitation vector	Network
Public exploit	N/A
Vulnerable software Subscribe	Squid Server applications / IDS/IPS systems, Firewalls and proxy servers
Vendor	Squid-cache.org

Security Bulletin

This security bulletin contains information about 2 vulnerabilities.

1) Improper Certificate Validation

EUVDB-ID: #VU57025

Risk: Medium

CVSSv3.1: 4.7 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-41611

CWE-ID: CWE-295 - Improper Certificate Validation

Exploit availability: No

Description

The vulnerability allows a remote attacker to perform a MitM attack.

The vulnerability exists due to improper certificate validation when the TLS server certificate is signed by multiple CAs. A remote attacker can perform a mand-in-the-middle attack against proxy server users.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Squid: 5.0.6 - 5.1

External links

http://github.com/squid-cache/squid/security/advisories/GHSA-47m4-g3mv-9q5r/

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.

2) Out-of-bounds read

EUVDB-ID: #VU50457

Risk: Medium

CVSSv3.1: 5.7 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-28116

CWE-ID: CWE-125 - Out-of-bounds read

Exploit availability: No

Description

The vulnerability allows a remote attacker to gain access to potentially sensitive information.

The vulnerability exists due to a boundary condition within the handling of the WCCP protocol. A remote attacker can send specially crafted data and corrupt Squids list of known WCCP routers and divert client traffic to attacker controlled routers.

This attack is limited to Squid proxy with WCCPv2 enabled and IP spoofing of a router IP address configured as trusted in squid.conf.