Bug 1299416 (CVE-2016-0741) - CVE-2016-0741 389-ds-base: worker threads do not detect abnormally closed connections causing DoS
Summary: CVE-2016-0741 389-ds-base: worker threads do not detect abnormally closed con...
Alias: CVE-2016-0741
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
Depends On: 1299417 1299418 1299757 1299758
Blocks: 1299421
TreeView+ depends on / blocked
Reported: 2016-01-18 10:28 UTC by Adam Mariš
Modified: 2020-09-13 21:38 UTC (History)
8 users (show)

Fixed In Version: 389-ds-base
Doc Type: Bug Fix
Doc Text:
An infinite-loop vulnerability was discovered in the 389 directory server, where the server failed to correctly handle unexpectedly closed client connections. A remote attacker able to connect to the server could use this flaw to make the directory server consume an excessive amount of CPU and stop accepting connections (denial of service).
Clone Of:
Last Closed: 2016-02-16 13:41:12 UTC

Attachments (Terms of Use)

System ID Private Priority Status Summary Last Updated
Github 389ds 389-ds-base issues 1743 0 None None None 2020-09-13 21:38:16 UTC
Red Hat Product Errata RHSA-2016:0204 0 normal SHIPPED_LIVE Important: 389-ds-base security and bug fix update 2016-02-16 15:47:59 UTC

Description Adam Mariš 2016-01-18 10:28:41 UTC
Quoting from the upstream bug:

When a connection is abruptly closed due to an error, and there is still some data left to be read (buffer offset vs buffer bytes), connection_threadmain starts to loop. The connection is marked as closed, which prevents the buffer bytes/offset to be updated (e.g. in connection_read_operation()). So the worker thread endlessly tries to read the "data" over and over, but it should just remove the connection from the conn table since it's marked as closed. While it's looping it's repeatedly taking the factory extension lock which creates a lot of contention with the other worker threads. Ultimately, all the worker threads are trying to read data on closed connections, and the server stops accepting new connections.

Upstream bug (includes patch):


Comment 1 Adam Mariš 2016-01-18 10:29:27 UTC
Created 389-ds-base tracking bugs for this issue:

Affects: fedora-all [bug 1299417]
Affects: epel-5 [bug 1299418]

Comment 7 Tomas Hoger 2016-01-22 13:35:27 UTC
Upstream commit:


The fix should be part of

Comment 12 errata-xmlrpc 2016-02-16 10:50:54 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7

Via RHSA-2016:0204 https://rhn.redhat.com/errata/RHSA-2016-0204.html

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