OpenLDAP 2.4.36 Remote Users Deny Of Service

2014.02.05

Credit: Vincent Danen

Risk: Medium

Local: No

Remote: Yes

CVE: CVE-2013-4449

CWE: N/A

CVSS Base Score: 4.3/10

Impact Subscore: 2.9/10

Exploitability Subscore: 8.6/10

Exploit range: Remote

Attack complexity: Medium

Authentication: No required

Confidentiality impact: None

Integrity impact: None

Availability impact: Partial

It was discovered that OpenLDAP, with the rwm overlay to slapd, could segfault if a user were able to query the directory and immediately unbind from the server. This seems to be due to the rwm overlay not doing reference counting properly, so rwm_conn_destroy frees the session context while rwm_op_search is using it. This condition also seems to require multiple cores/CPUs to trigger.
This was also reported upstream [1] and is currently unfixed.
[1] http://www.openldap.org/its/index.cgi/Incoming?id=7723

References:

https://bugzilla.redhat.com/show_bug.cgi?id=1019490

http://www.securitytracker.com/id/1029711

http://www.securityfocus.com/bid/63190

http://www.openwall.com/lists/oss-security/2013/10/19/3

http://www.openldap.org/its/index.cgi/Incoming?id=7723

http://rhn.redhat.com/errata/RHSA-2014-0126.html

See this note in RAW Version

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OpenLDAP 2.4.36 Remote Users Deny Of Service

References:

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