CVE-2020-27840: 
Kerberos vulnerability analysis and mitigation

CVE-2020-27840 is a vulnerability discovered in Samba, affecting all versions since Samba 4.0.0. The vulnerability involves spaces used in a string around a domain name (DN), which, while supposed to be ignored, can cause invalid DN strings with spaces to write a zero-byte into out-of-bounds memory, resulting in a crash (Samba Security, NVD).

The vulnerability is characterized by a heap corruption flaw that occurs when processing domain name strings. When spaces are present in DN strings, instead of being properly ignored, they can trigger an out-of-bounds memory write of a zero byte. The vulnerability has been assigned a CVSS v3.1 base score of 7.5 (HIGH) with the vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H, indicating it can be exploited remotely without requiring privileges or user interaction (NetApp Security).

The primary impact of this vulnerability is on system availability. When successfully exploited, it can cause the Samba AD DC LDAP server to crash. While non-fatal data corruption is possible, the most likely outcome is a denial of service condition. The vulnerability is particularly concerning as it can be triggered through LDAP bind requests before password verification, allowing anonymous attackers to exploit it (Samba Security).

The vulnerability has been patched in Samba versions 4.14.2, 4.13.7, and 4.12.14. No workarounds are available, and administrators are advised to upgrade to these patched versions as soon as possible (Gentoo Security, Samba Security).