GPO cache path traversal via unsanitized gPCFileSysPath allows Kerberos authentication bypass

Summary

A path traversal flaw was found in SSSD's AD GPO provider. The ad_gpo_extract_smb_components() function does not sanitize .. sequences in the gPCFileSysPath LDAP attribute, allowing an attacker with AD GPO management access to write files outside the GPO cache directory as root. On default RHEL configurations with SELinux enforcing, this can be used to inject Kerberos configuration leading to authentication bypass. SELinux blocks writes to most security-critical paths such as /etc/cron.d/. Red Hat severity: Moderate — CVSS 8 (CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H). Weakness: CWE-23. Affected Red Hat products: Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 6; Red Hat Enterprise Linux 7; Red Hat Enterprise Linux 8; Red Hat Enterprise Linux 9; Red Hat OpenShift Container Platform 4. Will not fix / out of support: Red Hat Enterprise Linux 6. Red Hat does not currently list a fixing RHSA for this CVE.