(Splunk Issues Fix) Python Hash Table Collision Bug Lets Remote Users Deny Service
SecurityTracker Alert ID: 1027720|
SecurityTracker URL: http://securitytracker.com/id/1027720
(Links to External Site)
Date: Nov 5 2012
Denial of service via network|
Fix Available: Yes Vendor Confirmed: Yes Exploit Included: Yes |
Version(s): prior to 5.0|
A vulnerability was reported in Python. A remote user can cause denial of service conditions. Splunk is affected.|
A remote user can send specially crafted POST request values to trigger hash collisions and cause significant performance degradation on the target server.
The original advisory is available at:
Alexander Klink of n.runs AG and Julian Walde of Technische Universitat Darmstadt reported this vulnerability. Scott A. Crosby and Dan S. Wallach of Rice University reported the theoretical attack.
A remote user can cause performance to degrade on the target server.|
Splunk has issued a fix (5.0).|
The Splunk advisory is available at:
|Underlying OS: Linux (Any), UNIX (AIX), UNIX (FreeBSD), UNIX (HP/UX), UNIX (macOS/OS X), UNIX (Solaris - SunOS), Windows (Any)|
This archive entry is a follow-up to the message listed below.|
Source Message Contents
Subject: [Full-disclosure] n.runs-SA-2012.003 - SPLUNK DoS HashDOS|
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)
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