Bug 1849509 (CVE-2020-10760) - CVE-2020-10760 samba: LDAP Use-after-free in Samba AD DC Global Catalog with paged_results and VLV
Summary: CVE-2020-10760 samba: LDAP Use-after-free in Samba AD DC Global Catalog with ...
Keywords:
Status: CLOSED NOTABUG
Alias: CVE-2020-10760
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: 1853276
Blocks: 1849490
TreeView+ depends on / blocked
 
Reported: 2020-06-22 05:12 UTC by Huzaifa S. Sidhpurwala
Modified: 2020-07-30 15:28 UTC (History)
17 users (show)

Fixed In Version: samba 4.10.17, samba 4.11.11, samba 4.12.4
Doc Type: If docs needed, set a value
Doc Text:
A use-after-free flaw was found in samba LDAP server used in a AC DC configuration. A Samba LDAP user could use this flaw to crash samba.
Clone Of:
Environment:
Last Closed: 2020-06-22 05:29:05 UTC


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System ID Priority Status Summary Last Updated
Samba Project 14402 None None None 2020-06-22 15:16:08 UTC

Description Huzaifa S. Sidhpurwala 2020-06-22 05:12:16 UTC
As per upstream advisory:

Samba 4.5 and later implements VLV - Virtual List View, and Samba 4.10 and later reimplemented the paged_results control using similar code.

This code is more memory-efficient, storing only a pointer to the object, not the returned object.  However this means parts of the original request must be retained

When these controls are used by a client that connects to the Global Catalog server, these modules failed to correctly retain the control data along with the request, causing a use-after-free and an abort when this is detected by the talloc library.

NOTE WELL: Unsupported Samba versions before Samba 4.7 use a single process for the LDAP servers.

All versions of Samba after Samba 4.11 use the 'prefork' process model to create a shared connection pool.  Crashing servers are restarted, but service is disrupted.

Comment 1 Huzaifa S. Sidhpurwala 2020-06-22 05:13:45 UTC
Acknowledgments:

Name: the Samba project
Upstream: Andrei Popa

Comment 4 Hardik Vyas 2020-06-23 08:48:04 UTC
Statement:

This flaw does not affect the version of samba shipped with Red Hat Enterprise Linux and Red Hat Gluster Storage 3 because there is no support for samba as Active Directory Domain Controller.

Comment 5 Huzaifa S. Sidhpurwala 2020-07-02 09:34:31 UTC
External References:

https://www.samba.org/samba/security/CVE-2020-10760.html

Comment 6 Huzaifa S. Sidhpurwala 2020-07-02 10:38:09 UTC
Created samba tracking bugs for this issue:

Affects: fedora-all [bug 1853276]


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