USN-1592-1: Python 2.7 vulnerabilities

Niels Heinen discovered that the urllib and urllib2 modules would process Location headers that specify a redirection to file: URLs. A remote attacker could exploit this to obtain sensitive information or cause a denial of service. This issue only affected Ubuntu 11.04. (CVE-2011-1521) It was discovered that SimpleHTTPServer did not use a charset parameter in the Content-Type HTTP header. An attacker could potentially exploit this to conduct cross-site scripting (XSS) attacks against Internet Explorer 7 users. This issue only affected Ubuntu 11.04. (CVE-2011-4940) It was discovered that Python distutils contained a race condition when creating the ~/.pypirc file. A local attacker could exploit this to obtain sensitive information. (CVE-2011-4944) It was discovered that SimpleXMLRPCServer did not properly validate its input when handling HTTP POST requests. A remote attacker could exploit this to cause a denial of service via excessive CPU utilization. (CVE-2012-0845) It was discovered that Python was susceptible to hash algorithm attacks. An attacker could cause a denial of service under certian circumstances. This update adds the '-R' command line option and honors setting the PYTHONHASHSEED environment variable to 'random' to salt str and datetime objects with an unpredictable value. (CVE-2012-1150)