Auth bypass in FreeBSD
CVE-2023-3326
pam_krb5 authenticates a user by essentially running kinit with the password, getting a ticket-granting ticket (tgt) from the Kerberos KDC (Key Distribution Center) over the network, as a way to verify the password. However, if a keytab is not provisioned on the system, pam_krb5 has no way to validate the response from the KDC, and essentially trusts the tgt provided over the network as being valid. In a non-default FreeBSD installation that leverages pam_krb5 for authentication and does not have a keytab provisioned, an attacker that is able to control both the password and the KDC responses can return a valid tgt, allowing authentication to occur for any user on the system.
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: 0.011 (64.3th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 64th percentile — 64.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.011 · newest: 0.011 · change: 0.000
Affected products
- FreeBSD — versions 13.1, 13.2, 13.1-RELEASE
Weakness classification (CWE)
Public proof-of-concept exploits
References
- security.FreeBSD.org/advisories/FreeBSD-SA-23:04.pam_krb5.asc (vendor-advisory, Mitigation, Vendor Advisory)
- security.netapp.com/advisory/ntap-20230714-0005/ (Third Party Advisory, third-party-advisory)
- security.FreeBSD.org/advisories/FreeBSD-SA-23:09.pam_krb5.asc (vendor-advisory)
Frequently asked questions
- What is CVE-2023-3326?
- CVE-2023-3326 is a critical-severity vulnerability in FreeBSD, classified under Incorrect Implementation of Authentication Algorithm. CVSS score: 9.8/10. Published 2023-06-22.
- How severe is CVE-2023-3326?
- Critical severity. CVSS v3 base score is 9.8 out of 10.
- Is CVE-2023-3326 known to be exploited?
- 4 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.