Vulnerability Report

CVE-2019-12520

Title: Squid-Cache Squid Improper Input Validation

Improper Input Validation

Proof Of Concept

No public PoC currently indexed for CVE-2019-12520.

CWE Category CWE-20
Published Date Apr 15, 2020
Modified Date Nov 21, 2024
Exploit Status Not Found
Score 7.5 CVSS v3.1
Exploit Probability (EPSS)
3.93%

Vulnerability Summary

CVE-2019-12520: 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.

Impacted Vendors

S
squid 1
S
squid-cache 1

Reference Links

http://www.squid-cache.org/Versions/v4/ http://www.squid-cache.org/Versions/v4/changesets/ https://github.com/squid-cache/squid/commits/v4 https://gitlab.com/jeriko.one/security/-/blob/master/squid/CVEs/CVE-2019-12520.txt https://lists.debian.org/debian-lts-announce/2020/07/msg00009.html https://security.netapp.com/advisory/ntap-20210205-0006/ https://usn.ubuntu.com/4446-1/ https://www.debian.org/security/2020/dsa-4682 http://www.squid-cache.org/Versions/v4/ http://www.squid-cache.org/Versions/v4/changesets/ https://github.com/squid-cache/squid/commits/v4 https://gitlab.com/jeriko.one/security/-/blob/master/squid/CVEs/CVE-2019-12520.txt https://lists.debian.org/debian-lts-announce/2020/07/msg00009.html https://security.netapp.com/advisory/ntap-20210205-0006/ https://usn.ubuntu.com/4446-1/ https://www.debian.org/security/2020/dsa-4682
CVSS v3.1
Source Entity [email protected]
Severity HIGH
7.5
Attack Vector
NETWORK
Complexity
LOW
Privileges
N/A
Interaction
NONE
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
UNCHANGED
RAW VECTOR CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
CVSS v2.0
Source Entity [email protected]
Severity MEDIUM
5.0
Access Vector
N/A
Authentication
N/A
RAW VECTOR AV:N/AC:L/Au:N/C:P/I:N/A:N

Associated Attack Patterns (CAPEC)

Total: Patterns

CVE-2019-12520 Exploits & PoCs (Proof Of Concept)

No public PoCs found in our database for this CVE.

MODIFIED

Vulnerability data or affected products updated.

PUBLISHED

Vulnerability first announced in NVD.

Attack Vector Matrix

Access Vector NETWORK
Complexity LOW
Privileges N/A
Interaction NONE
CVSS Vector String CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Affected Stack

No specific products linked.