Vulnerability identifier: #VU29391

Vulnerability risk: Medium

CVSSv3.1: 4.3 [CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-15049

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 perform cache poisoning attack.

The vulnerability exists in the way Squid processes client's requests. A remote client can send specially crafted data in the request to perform request smuggling and poison the HTTP cache contents with crafted HTTP(S) request messages.

Successful exploitation of the vulnerability requires an upstream server to participate in the smuggling and generate the poison response sequence.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Squid: 5.0 - 5.0.2, 4.0 - 4.11, 3.0 - 3.5.28, 2.7 - 2.7.STABLE9, 2.6 - 2.6.stable24, 2.5 - 2.5_stable9, 2.4 - 2.4_stable_3, 2.3 - 2.3_stable5, 2.2 - 2.2.stable5, 2.1 - 2.1_patch2, 2.0 - 2.0_patch2

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External links
http://github.com/squid-cache/squid/security/advisories/GHSA-qf3v-rc95-96j5

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

Is there known malware, which exploits this vulnerability?

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