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Vulnerability · Published Jun 22, 2023 · Assigned by freebsd

CVE-2023-3326Network authentication attack via pam_krb5

Critical 9.8

In plain English

A critical-severity security flaw in FreeBSD from FreeBSD. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.1% (higher than 66% of all known vulnerabilities).

Severity (CVSS NVD)9.8Critical
Exploit odds (30 days)1.1%top 34.2% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12libpam-krb5no fix listedDEBIAN-CVE-2023-3326
Debian:13libpam-krb5no fix listedDEBIAN-CVE-2023-3326
Debian:14libpam-krb5no fix listedDEBIAN-CVE-2023-3326
Ubuntu:22.04:LTSlibpam-krb5no fix listedUBUNTU-CVE-2023-3326
Ubuntu:24.04:LTSlibpam-krb5no fix listedUBUNTU-CVE-2023-3326
Ubuntu:25.10libpam-krb5no fix listedUBUNTU-CVE-2023-3326
Ubuntu:26.04:LTSlibpam-krb5no fix listedUBUNTU-CVE-2023-3326
Ubuntu:26.10libpam-krb5no fix listedUBUNTU-CVE-2023-3326
Ubuntu:22.04:LTSsssdno fix listedUBUNTU-CVE-2023-3326
Ubuntu:24.04:LTSsssdno fix listedUBUNTU-CVE-2023-3326
Ubuntu:25.10sssdno fix listedUBUNTU-CVE-2023-3326
Ubuntu:26.04:LTSsssdno fix listedUBUNTU-CVE-2023-3326
Ubuntu:26.10sssdno fix listedUBUNTU-CVE-2023-3326

Affected products (as reported)

VendorProductVersions
FreeBSD FreeBSD 13.2-RELEASE – before 13.2-RELEASE-p113.1-RELEASE – before 13.1-RELEASE-p812.4-RELEASE – before 12.4-RELEASE-p3

Weakness: CWE-303

References