Squid Web Proxy up to 4.14/5.0.5 Range Request denial of service

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CVSS Meta Temp Score
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5.1$0-$5k0.00

A vulnerability classified as problematic has been found in Squid Web Proxy up to 4.14/5.0.5 (Firewall Software). Affected is some unknown functionality of the component Range Request Handler. The manipulation with an unknown input leads to a denial of service vulnerability. CWE is classifying the issue as CWE-404. This is going to have an impact on availability. CVE summarizes:

An issue was discovered in Squid before 4.15 and 5.x before 5.0.6. Due to an input-validation bug, it is vulnerable to a Denial of Service attack (against all clients using the proxy). A client sends an HTTP Range request to trigger this.

The weakness was presented 05/28/2021. The advisory is shared for download at github.com. This vulnerability is traded as CVE-2021-31808 since 04/26/2021. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. There are neither technical details nor an exploit publicly available. The MITRE ATT&CK project declares the attack technique as T1499.

Upgrading to version 4.15 or 5.0.6 eliminates this vulnerability. Applying a patch is able to eliminate this problem. The bugfix is ready for download at squid-cache.org. The best possible mitigation is suggested to be upgrading to the latest version.

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CVSSv3infoedit

VulDB Meta Base Score: 5.3
VulDB Meta Temp Score: 5.1

VulDB Base Score: 5.3
VulDB Temp Score: 5.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2infoedit

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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfoedit

Class: Denial of service
CWE: CWE-404
ATT&CK: T1499

Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfoedit

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfoedit

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Web Proxy 4.15/5.0.6
Patch: squid-cache.org

Timelineinfoedit

04/26/2021 CVE assigned
05/28/2021 +32 days Advisory disclosed
05/28/2021 +0 days VulDB entry created
05/30/2021 +2 days VulDB last update

Sourcesinfoedit

Vendor: http://www.squid-cache.org/

Advisory: github.com
Status: Confirmed

CVE: CVE-2021-31808 (🔒)

Entryinfoedit

Created: 05/28/2021 06:25 AM
Updated: 05/30/2021 11:44 AM
Changes: (5) vulnerability_cvss2_vuldb_tempscore vulnerability_cvss3_meta_tempscore vulnerability_cvss3_vuldb_tempscore source_cve_assigned source_cve_nvd_summary
Complete: 🔍

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