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
an attacker to produce hash collisions for the hash table string hashing
function. 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 Splunkweb
(for example to the login form endpoint) with colliding keys. Even a moderate
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)
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