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Security and Update Advisories

security

#21

Discussion is here: Yeahhh 3 fresh intel security holes


#22

Samba security issue announces tomorrow.

Hi,

this is a heads-up that there will be Samba security updates on
Tuesday, November 27 2018 (~ 8-11am UTC). Please make sure that your Samba
servers will be updated soon after the release!

Impacted components:

  • AD DC (CVSS 6.5, Medium)

We apologise for the short pre-notification notice.


Update:

TLDR; - This appears to be the most serious one.

All versions of Samba from 4.0.0 onwards are vulnerable to infinite
query recursion caused by CNAME loops. Any dns record can be added via
ldap by an unprivileged user

Here’s all of it:

Security Announcement

=======
Details
=======

o CVE-2018-14629:
All versions of Samba from 4.0.0 onwards are vulnerable to infinite
query recursion caused by CNAME loops. Any dns record can be added via
ldap by an unprivileged user using the ldbadd tool, so this is a
security issue.

o CVE-2018-16841:
When configured to accept smart-card authentication, Samba’s KDC will call
talloc_free() twice on the same memory if the principal in a validly signed
certificate does not match the principal in the AS-REQ.

This is only possible after authentication with a trusted certificate.

talloc is robust against further corruption from a double-free with
talloc_free() and directly calls abort(), terminating the KDC process.

There is no further vulnerability associated with this issue, merely a
denial of service.

o CVE-2018-16851:
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.

o CVE-2018-16852:
During the processing of an DNS zone in the DNS management DCE/RPC server,
the internal DNS server or the Samba DLZ plugin for BIND9, if the
DSPROPERTY_ZONE_MASTER_SERVERS property or DSPROPERTY_ZONE_SCAVENGING_SERVERS
property is set, the server will follow a NULL pointer and terminate.

There is no further vulnerability associated with this issue, merely a
denial of service.

o CVE-2018-16853:
A user in a Samba AD domain can crash the KDC when Samba is built in the
non-default MIT Kerberos configuration.

With this advisory we clarify that the MIT Kerberos build of the Samba
AD DC is considered experimental. Therefore the Samba Team will not
issue security patches for this configuration.

o CVE-2018-16857:
AD DC Configurations watching for bad passwords (to restrict brute forcing
of passwords) in a window of more than 3 minutes may not watch for bad
passwords at all.

These are fixed in versions 4.9.3, 4.8.7 and 4.7.12.


#23

Humble bundle hack