CVE-2012-1150

First published: Tue Nov 01 2011(Updated: )

Julian Wälde and Alexander Klink reported a flaw in the hash function used in the implementation of the Python dictionaries (associative arrays). A specially-crafted set of keys could trigger hash function collisions, which degrade dictionary performance by changing hash table operations complexity from an expected/average O(1) to the worst case O(n). Reporters were able to find colliding strings efficiently using meet in the middle attack. As various web application frameworks for Python automatically pre-fill certain dictionaries with data from the HTTP request (such as GET or POST parameters) for Python web application, a remote attacker could use this flaw to make Python interpreter use excessive amount of CPU time by sending a POST request with large amount of parameters which hash to the same value. This problem is similar to the issue that was previously reported for and fixed in e.g. perl: <a href="http://www.cs.rice.edu/~scrosby/hash/CrosbyWallach_UsenixSec2003.pdf">http://www.cs.rice.edu/~scrosby/hash/CrosbyWallach_UsenixSec2003.pdf</a>

Credit: secalert@redhat.com secalert@redhat.com

Never miss a vulnerability like this again

Sign up to SecAlerts for real-time vulnerability data matched to your software, aggregated from hundreds of sources.

Read MoreStart Free Trial

• collector/nvd-index
• agent/type
• agent/first-publish-date
• collector/launchpad-cve
• source/Launchpad
• collector/redhat-bugzilla
• source/Red Hat
• alias/CVE-2012-1150
• agent/author
• agent/last-modified-date
• agent/weakness
• agent/severity
• collector/nvd-cve
• source/NVD
• agent/software-canonical-lookup
• agent/event
• agent/description
• agent/remedy
• agent/references
• agent/tags
• collector/security-tracker-debian
• source/Debian
• agent/softwarecombine
• collector/usn-cve
• source/Ubuntu
• vendor/python
• canonical/python python
• version/python python/2.6.7
• version/python python/0.9.0
• version/python python/0.9.1
• version/python python/1.2
• version/python python/1.3
• version/python python/1.5.2
• version/python python/1.6
• version/python python/1.6.1
• version/python python/2.0
• version/python python/2.0.1
• version/python python/2.1
• version/python python/2.1.1
• version/python python/2.1.2
• version/python python/2.1.3
• version/python python/2.2
• version/python python/2.2.1
• version/python python/2.2.2
• version/python python/2.2.3
• version/python python/2.3.1
• version/python python/2.3.2
• version/python python/2.3.3
• version/python python/2.3.4
• version/python python/2.3.5
• version/python python/2.3.7
• version/python python/2.4.1
• version/python python/2.4.2
• version/python python/2.4.3
• version/python python/2.4.4
• version/python python/2.4.6
• version/python python/2.5.1
• version/python python/2.5.2
• version/python python/2.5.3
• version/python python/2.5.4
• version/python python/2.5.6
• version/python python/2.5.150
• version/python python/2.6.1
• version/python python/2.6.2
• version/python python/2.6.3
• version/python python/2.6.4
• version/python python/2.6.5
• version/python python/2.6.6
• version/python python/2.6.2150
• version/python python/2.6.6150
• version/python python/2.7.1
• version/python python/2.7.1-rc1
• version/python python/2.7.2-rc1
• version/python python/2.7.1150
• version/python python/2.7.2150
• version/python python/3.0
• version/python python/3.0.1
• version/python python/3.1
• version/python python/3.1.1
• version/python python/3.1.2
• version/python python/3.1.3
• version/python python/3.1.4
• version/python python/3.2
• version/python python/3.2-alpha
• version/python python/3.2.2150
• package-manager/debian