Bug 2021726 (CVE-2021-3738) - CVE-2021-3738 samba: Use after free in Samba AD DC RPC server
Summary: CVE-2021-3738 samba: Use after free in Samba AD DC RPC server
Keywords:
Status: CLOSED NOTABUG
Alias: CVE-2021-3738
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: 2021727
Blocks: 1976705 2003971
TreeView+ depends on / blocked
 
Reported: 2021-11-10 03:22 UTC by Huzaifa S. Sidhpurwala
Modified: 2022-03-01 09:29 UTC (History)
16 users (show)

Fixed In Version: samba 4.15.2, samba 4.14.10, samba 4.13.14
Doc Type: If docs needed, set a value
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Clone Of:
Environment:
Last Closed: 2021-11-10 04:27:26 UTC


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Description Huzaifa S. Sidhpurwala 2021-11-10 03:22:57 UTC
As per upstream report:


In DCE/RPC it is possible to share the handles (cookies for resource state) between multiple connections via a mechanism called 'association groups'. These handles can reference connections to our sam.ldb database. However while the database was correctly shared, the user credentials state was only pointed at, and when one connection within that association group ended, the database would be left pointing at an invalid 'struct session_info'.

The most likely outcome here is a crash, but it is possible that the use-after-free could instead allow different user state to be pointed at and this might allow more privileged access.

Comment 1 Huzaifa S. Sidhpurwala 2021-11-10 03:23:21 UTC
Created samba tracking bugs for this issue:

Affects: fedora-all [bug 2021727]


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