Python contains a vulnerability that could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on a targeted system.
The vulnerability is due to improper handling of the HTTP POST request by the affected software. An unauthenticated, remote attacker could exploit the vulnerability by submitting multiple HTTP POST requests to the affected software. Processing the malicious requests could cause the application to consume excessive CPU resources, resulting in a DoS condition.
Python has confirmed the vulnerability and updated software is available.
Indicators of Compromise
The following products are vulnerable:
Python versions prior to 2.6.8
Python versions prior to 2.7.3
Python versions prior to 3.1.5
Python versions prior to 3.2.3
The vulnerability is in the implementation of associative arrays in the code that handles the hashing functionality in the affected software. While processing the HTTP POST request, the affected software fails to perform sufficient validation of user-supplied input parameters. These parameters are used as keys when inserting hash function data to an array, and processing multiple key values may trigger a hash function collision.
An unauthenticated, remote attacker could exploit the vulnerability by transmitting specially crafted HTTP POST requests that are designed to supply a large number of input requests to the affected application. Processing the malicious requests could trigger hash function collisions and consume excessive CPU resources, resulting in a DoS condition on the system.
To exploit this vulnerability, the attacker would need to send crafted requests to the targeted system. To achieve this objective, the attacker may need access to trusted, internal networks. This access requirement decreases the likelihood of a successful exploit.
Administrators are advised to apply the appropriate updates.
Administrators may consider using IP-based access control lists (ACLs) to allow only trusted systems to access the affected systems.
Administrators are advised to allow only trusted users to have network access.
Administrators are advised to monitor affected systems.
Python has released a security advisory at the following link: Issue 13703
Apple has released a security advisory at the following link: HT6011
MontaVista Software has released a changelog for registered users on June 26, 2013, at the following link: MontaVista Security Fixes
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Cisco Multivendor Vulnerability Alerts respond to vulnerabilities identified in third-party vendors' products. These alerts contain information compiled from diverse sources and provide comprehensive technical descriptions, objective analytical assessments, workarounds and practical safeguards, and links to vendor advisories and patches.