#VU51248 Inconsistent interpretation of HTTP requests in Squid - CVE-2020-25097

Vulnerability identifier: #VU51248

Vulnerability risk: Medium

CVSSv4.0: 2.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2020-25097

CWE-ID: CWE-444

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Squid
Server applications / IDS/IPS systems, Firewalls and proxy servers

Vendor: Squid-cache.org

Description

The vulnerability allows a remote attacker to preform HTTP request smuggling attacks.

The vulnerability exists due to improper validation of HTTP requests. A remote attacker can send a specially crafted HTTP request to the server and smuggle arbitrary HTTP headers.

Successful exploitation of vulnerability may allow an attacker to poison HTTP cache and perform phishing attacks.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Squid: 2.0.release - 2.0.patch2, 2.1.release - 2.1.pre4, 2.2.stable1 - 2.2.pre2, 2.3.stable1 - 2.3, 2.4.stable1 - 2.4_9, 2.5_.stable1 - 2.5.9, 2.6.stable1 - 2.6, 2.7.stable1 - 2.7, 3.0.stable1 - 3.5.28, 4.0 - 4.13, 5.0 - 5.0.4

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External links
https://github.com/squid-cache/squid/security/advisories/GHSA-jvf6-h9gj-pmj6/
https://www.squid-cache.org/Versions/v4/changesets/SQUID-2020_11.patch

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Q & A

Can this vulnerability be exploited remotely?

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

Is there known malware, which exploits this vulnerability?

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