Bug 1711837 (CVE-2019-12436) - CVE-2019-12436 samba: NULL pointer dereference in Samba LDAP server leading to crash and Dos
Summary: CVE-2019-12436 samba: NULL pointer dereference in Samba LDAP server leading t...
Keywords:
Status: CLOSED NOTABUG
Alias: CVE-2019-12436
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
URL:
Whiteboard:
Depends On: 1721873
Blocks: 1711838
TreeView+ depends on / blocked
 
Reported: 2019-05-20 08:30 UTC by Marian Rehak
Modified: 2021-02-16 21:55 UTC (History)
24 users (show)

Fixed In Version: samba 4.10.5
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Environment:
Last Closed: 2019-06-19 08:06:29 UTC
Embargoed:

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Description Marian Rehak 2019-05-20 08:30:47 UTC 
As per upstream advisory:

A user with read access to the LDAP server can crash the LDAP server process.  Depending on the Samba version and the choice of process model, this may crash only the user's own connection.

Specifically, while in Samba 4.10 the default is for one process per connected client, site-specific configuration trigger can change this.

Samba 4.10 also supports the 'prefork' process model and by using the -M option to 'samba' and a 'single' process model. Both of these share on process between multiple clients.
Comment 1 Riccardo Schirone 2019-05-22 10:38:24 UTC 
Mitigation:

Return to the default configuration by running 'samba' with -M standard, however this may consume more memory.
Comment 3 Huzaifa S. Sidhpurwala 2019-06-10 05:07:30 UTC 
Acknowledgments:

Name: The samba project (Zombie Ryushu)
Comment 4 Huzaifa S. Sidhpurwala 2019-06-10 06:38:48 UTC 
Upstream bug: https://bugzilla.samba.org/show_bug.cgi?id=13951
Comment 6 Huzaifa S. Sidhpurwala 2019-06-19 08:02:26 UTC 
External References:

https://www.samba.org/samba/security/CVE-2019-12436.html
Comment 7 Huzaifa S. Sidhpurwala 2019-06-19 08:02:53 UTC 
Created samba tracking bugs for this issue:

Affects: fedora-all [bug 1721873]
Comment 8 Hardik Vyas 2019-06-19 08:10:33 UTC 
Statement:

This issue did not affect the version of samba as shipped with 'Red Hat Gluster Storage 3' as they did not include support for Active Directory Domain Controller.
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