Auth bypass in Squid-Cache Squid
CVE-2019-12524
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.
Vulnerability class: Broken Authentication
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.039 (89.8th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 90th percentile — 89.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.043 · newest: 0.039 · change: -0.004
Affected products
- Squid-Cache Squid
- Canonical Ubuntu Linux — versions 16.04, 18.04
- Debian Linux — versions 9.0, 10.0
Weakness classification (CWE)
Public proof-of-concept exploits
References
- gitlab.com/jeriko.one/security/-/blob/master/squid/CVEs/CVE-2019-12524.txt (Third Party Advisory)
- www.debian.org/security/2020/dsa-4682 (vendor-advisory, Third Party Advisory)
- lists.debian.org/debian-lts-announce/2020/07/msg00009.html (mailing-list, Mailing List, Third Party Advisory)
- usn.ubuntu.com/4446-1/ (vendor-advisory, Third Party Advisory)
- security.netapp.com/advisory/ntap-20210205-0006/ (Third Party Advisory)
Frequently asked questions
- What is CVE-2019-12524?
- CVE-2019-12524 is a critical-severity vulnerability in Squid-Cache Squid, classified under Missing Authentication for Critical Function. CVSS score: 9.8/10. Published 2020-04-15.
- How severe is CVE-2019-12524?
- Critical severity. CVSS v3 base score is 9.8 out of 10.
- Is CVE-2019-12524 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.