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n.runs-SA-2012.003 - SPLUNK DoS HashDOS
From: <security () nruns com>
Date: Fri, 2 Nov 2012 16:42:39 +0100
Vendors: Splunk Inc., http://www.splunk.com
Product: Splunk 4.3.x (+ possibly earlier versions)
Vulnerability: Unauth. remote denial of service against splunkweb
Tracking IDs: CVE-2012-1150
2012/09/03 Reported the issue via Splunk's website
2012/09/04 Splunk responds and assigns tracking ID, plans fix for 5.0.
Replacing the Python version in a maintenance release
was considered too risky.
2012/10/25 Splunk informs us that 5.0 will be available on November 1st.
2012/10/29 Splunk 5.0 is released.
Splunkweb uses Python 2.7.2, which suffers from a vulnerability which allows
attacker to produce hash collisions for the hash table string hashing
This leads to an O(n^2) complexity when inserting n keys (see
An attacker can abuse this vulnerability by sending a POST request to
(for example to the login form endpoint) with colliding keys. Even a
amount of POST data leads to a 100% CPU usage for the splunkweb process.
Denial of service (CPU exhaustion) against the Splunk server.
This issue has been fixed in Splunk 5.0 by updating the Python version
to 2.7.3 and enabling hash randomization.
Alexander Klink, n.runs AG (discovery)
This advisory and upcoming advisories:
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- n.runs-SA-2012.003 - SPLUNK DoS HashDOS security (Nov 02)