Amazon Linux 2 : squid (ALASSQUID4-2023-008)

critical Nessus Plugin ID 181963

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Synopsis

The remote Amazon Linux 2 host is missing a security update.

Description

The version of squid installed on the remote host is prior to 4.11-1. It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2SQUID4-2023-008 advisory.

A flaw was found in Squid through version 4.7. When handling the tag esi:when, when ESI is enabled, Squid calls the ESIExpression::Evaluate function which uses a fixed stack buffer to hold the expression. While processing the expression, there is no check to ensure that the stack won't overflow. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.
(CVE-2019-12519)

A flaw was found in squid. When Squid is parsing ESI, it keeps the ESI elements in ESIContext. ESIContext contains a buffer for holding a stack of ESIElements. When a new ESIElement is parsed, it is added via addStackElement. addStackElement has a check for the number of elements in this buffer, but it's off by 1, leading to a Heap Overflow of 1 element. The overflow is within the same structure so it can't affect adjacent memory blocks, and thus just leads to a crash while processing. (CVE-2019-12521)

An issue was discovered in Squid 3.3.9 through 3.5.28 and 4.x through 4.7. When Squid is configured to use Digest authentication, it parses the header Proxy-Authorization. It searches for certain tokens such as domain, uri, and qop. Squid checks if this token's value starts with a quote and ends with one. If so, it performs a memcpy of its length minus 2. Squid never checks whether the value is just a single quote (which would satisfy its requirements), leading to a memcpy of its length minus 1. (CVE-2019-12525)

A flaw was found in Squid, where a remote attacker can replay a sniffed Digest Authentication nonce to gain access to resources that are otherwise forbidden. This issue occurs because the attacker can overflow the nonce reference counter, which results in remote code execution if the pooled token credentials are freed. (CVE-2020-11945)

Tenable has extracted the preceding description block directly from the tested product security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

Solution

Run 'yum update squid' to update your system.

Plugin Details

Severity: Critical

ID: 181963

File Name: al2_ALASSQUID4-2023-008.nasl

Version: 1.1

Type: local

Agent: unix

Family: Amazon Linux Local Security Checks

Published: 9/27/2023

Updated: 12/11/2024

Supported Sensors: Agentless Assessment, Continuous Assessment, Frictionless Assessment Agent, Frictionless Assessment AWS, Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 5.9

CVSS v2

Risk Factor: High

Base Score: 7.5

Temporal Score: 5.5

Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P

CVSS Score Source: CVE-2020-11945

CVSS v3

Risk Factor: Critical

Base Score: 9.8

Temporal Score: 8.5

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

CPE: cpe:/o:amazon:linux:2, p-cpe:/a:amazon:linux:squid, p-cpe:/a:amazon:linux:squid-debuginfo

Required KB Items: Host/local_checks_enabled, Host/AmazonLinux/release, Host/AmazonLinux/rpm-list

Exploit Ease: No known exploits are available

Patch Publication Date: 8/21/2023

Vulnerability Publication Date: 7/11/2019

Reference Information

CVE: CVE-2019-12519, CVE-2019-12521, CVE-2019-12525, CVE-2020-11945

Detections

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