Amazon Linux 2 : squid (ALASSQUID4-2023-009)

critical Nessus Plugin ID 181962

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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 4.15-1. It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2SQUID4-2023-009 advisory.

- An issue was discovered in Squid through 4.7 and 5. When receiving a request, Squid checks its cache to see if it can serve up a response. It does this by making a MD5 hash of the absolute URL of the request.
If found, it servers the request. The absolute URL can include the decoded UserInfo (username and password) for certain protocols. This decoded info is prepended to the domain. This allows an attacker to provide a username that has special characters to delimit the domain, and treat the rest of the URL as a path or query string. An attacker could first make a request to their domain using an encoded username, then when a request for the target domain comes in that decodes to the exact URL, it will serve the attacker's HTML instead of the real HTML. On Squid servers that also act as reverse proxies, this allows an attacker to gain access to features that only reverse proxies can use, such as ESI. (CVE-2019-12520)

- An issue was discovered in Squid through 4.7. When handling requests from users, Squid checks its rules to see if the request should be denied. Squid by default comes with rules to block access to the Cache Manager, which serves detailed server information meant for the maintainer. This rule is implemented via url_regex. The handler for url_regex rules URL decodes an incoming request. This allows an attacker to encode their URL to bypass the url_regex check, and gain access to the blocked resource. (CVE-2019-12524)

- An issue was discovered in Squid 4.9 through 4.17 and 5.0.6 through 5.6. Due to inconsistent handling of internal URIs, there can be Exposure of Sensitive Information about clients using the proxy via an HTTPS request to an internal cache manager URL. This is fixed in 5.7. (CVE-2022-41317)

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: 181962

File Name: al2_ALASSQUID4-2023-009.nasl

Version: 1.0

Type: local

Agent: unix

Family: Amazon Linux Local Security Checks

Published: 9/27/2023

Updated: 9/27/2023

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-2019-12524

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: 9/14/2023

Vulnerability Publication Date: 4/15/2020

Reference Information

CVE: CVE-2019-12520, CVE-2019-12524, CVE-2022-41317

Detections

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