CVE-2018-16851

Samba from version 4.0.0 and before versions 4.7.12, 4.8.7, 4.9.3 is vulnerable to a denial of service. During the processing of an LDAP search before Samba's AD DC returns the LDAP entries to the client, the entries are cached in a single memory object with a maximum size of 256MB. When this size is reached, the Samba process providing the LDAP service will follow the NULL pointer, terminating the process. There is no further vulnerability associated with this issue, merely a denial of service.

Samba from version 4.0.0 and before versions 4.7.12, 4.8.7, 4.9.3 is vulnerable to a denial of service. During the processing of an LDAP search before Samba's AD DC returns the LDAP entries to the client, the entries are cached in a single memory object with a maximum size of 256MB. When this size is reached, the Samba process providing the LDAP service will follow the NULL pointer, terminating the process. There is no further vulnerability associated with this issue, merely a denial of service.

Florian Stuelpner discovered that Samba is vulnerable to infinite query recursion caused by CNAME loops, resulting in denial of service (CVE-2018-14629).

Alex MacCuish discovered that a user with a valid certificate or smart card can crash the Samba AD DC's KDC when configured to accept smart-card authentication (CVE-2018-16841).

Garming Sam of the Samba Team and Catalyst discovered a NULL pointer dereference vulnerability in the Samba AD DC LDAP server allowing a user able to read more than 256MB of LDAP entries to crash the Samba AD DC's LDAP server (CVE-2018-16851).

Samba has been updated to version 4.7.12 of the 4.7.x stable branch, and the tdb, talloc, tevent, ldb, and cmocka packages have also been updated.

The sssd package has also been rebuilt against the updated ldb.

These are all security issues fixed in the ctdb-4.14.6+git.182.2205d5224e3-1.1 package on the GA media of openSUSE Tumbleweed.

This update for samba fixes the following issues:

Update to samba version 4.7.11.

Security issues fixed:

• CVE-2018-14629: Fixed CNAME loops in Samba AD DC DNS server (bsc#1116319).
• CVE-2018-16841: Fixed segfault on PKINIT when mis-matching principal (bsc#1116320).
• CVE-2018-16851: Fixed NULL pointer de-reference in Samba AD DC LDAP server (bsc#1116322).
• CVE-2018-16853: Mark MIT support for the AD DC experimental (bsc#1116324).

Non-security issues fixed:

• Fixed do not take over stderr when there is no log file (bsc#1101499).
• Fixed ctdb_mutex_ceph_rados_helper deadlock; (bsc#1102230).
• Fixed ntlm authentications with 'winbind use default domain = yes'; (bsc#1068059).
• Fixed idmap_rid to have primary group other than 'Domain Users'; (bsc#1087931).
• Fixed windows domain with one way trust that was not working (bsc#1087303).

Florian Stuelpner discovered that Samba incorrectly handled CNAME records. A remote attacker could use this issue to cause Samba to crash, resulting in a denial of service. (CVE-2018-14629)

Alex MacCuish discovered that Samba incorrectly handled memory when configured to accept smart-card authentication. A remote attacker could possibly use this issue to cause Samba to crash, resulting in a denial of service. (CVE-2018-16841)

Garming Sam discovered that Samba incorrectly handled memory when processing LDAP searches. A remote attacker could possibly use this issue to cause Samba to crash, resulting in a denial of service. (CVE-2018-16851)