Improper Input Validation Affecting squid-sysvinit package, versions *


Severity

Recommended
medium

Based on Red Hat Enterprise Linux security rating.

Threat Intelligence

EPSS
0.37% (73rd percentile)

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  • Snyk IDSNYK-RHEL7-SQUIDSYSVINIT-1383248
  • published26 Jul 2021
  • disclosed24 Apr 2020

Introduced: 24 Apr 2020

CVE-2019-12520  (opens in a new tab)
CWE-20  (opens in a new tab)

How to fix?

There is no fixed version for RHEL:7 squid-sysvinit.

NVD Description

Note: Versions mentioned in the description apply only to the upstream squid-sysvinit package and not the squid-sysvinit package as distributed by RHEL. See How to fix? for RHEL:7 relevant fixed versions and status.

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.

CVSS Scores

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