CVE-2019-12520 Detail

Current Description

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.


View Analysis Description

Severity



CVSS 3.x Severity and Metrics:

NIST CVSS score
NIST: NVD
Base Score:  7.5 HIGH
Vector:  CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N


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Note: NVD Analysts have published a CVSS score for this CVE based on publicly available information at the time of analysis. The CNA has not provided a score within the CVE List.

References to Advisories, Solutions, and Tools

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Hyperlink Resource
http://www.squid-cache.org/Versions/v4/ Release Notes  Vendor Advisory 
http://www.squid-cache.org/Versions/v4/changesets/ Release Notes  Vendor Advisory 
https://github.com/squid-cache/squid/commits/v4 Patch  Third Party Advisory 
https://gitlab.com/jeriko.one/security/-/blob/master/squid/CVEs/CVE-2019-12520.txt Third Party Advisory 
https://lists.debian.org/debian-lts-announce/2020/07/msg00009.html
https://usn.ubuntu.com/4446-1/
https://www.debian.org/security/2020/dsa-4682

Weakness Enumeration

CWE-ID CWE Name Source
CWE-20 Improper Input Validation cwe source acceptance level NIST  

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Change History

4 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2019-12520
NVD Published Date:
04/15/2020
NVD Last Modified:
08/05/2020
Source:
MITRE