RHSA-2011:0492 - Security Advisory

Topic

Updated python packages that fix multiple security issues are now available
for Red Hat Enterprise Linux 5.

The Red Hat Security Response Team has rated this update as having moderate
security impact. Common Vulnerability Scoring System (CVSS) base scores,
which give detailed severity ratings, are available for each vulnerability
from the CVE links in the References section.

Description

Python is an interpreted, interactive, object-oriented programming
language.

A flaw was found in the Python urllib and urllib2 libraries where they
would not differentiate between different target URLs when handling
automatic redirects. This caused Python applications using these modules to
follow any new URL that they understood, including the "file://" URL type.
This could allow a remote server to force a local Python application to
read a local file instead of the remote one, possibly exposing local files
that were not meant to be exposed. (CVE-2011-1521)

A race condition was found in the way the Python smtpd module handled new
connections. A remote user could use this flaw to cause a Python script
using the smtpd module to terminate. (CVE-2010-3493)

An information disclosure flaw was found in the way the Python
CGIHTTPServer module processed certain HTTP GET requests. A remote attacker
could use a specially-crafted request to obtain the CGI script's source
code. (CVE-2011-1015)

A buffer over-read flaw was found in the way the Python Expat parser
handled malformed UTF-8 sequences when processing XML files. A
specially-crafted XML file could cause Python applications using the Python
Expat parser to crash while parsing the file. (CVE-2009-3720)

This update makes Python use the system Expat library rather than its own
internal copy; therefore, users must have the version of Expat shipped with
RHSA-2009:1625 installed, or a later version, to resolve the CVE-2009-3720
issue.

All Python users should upgrade to these updated packages, which contain
backported patches to correct these issues.

Solution

Before applying this update, make sure all previously-released errata
relevant to your system have been applied.

This update is available via the Red Hat Network. Details on how to
use the Red Hat Network to apply this update are available at
https://access.redhat.com/kb/docs/DOC-11259

Affected Products

• Red Hat Enterprise Linux Server 5 x86_64
• Red Hat Enterprise Linux Server 5 ia64
• Red Hat Enterprise Linux Server 5 i386
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 5.6 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 5.6 ia64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 5.6 i386
• Red Hat Enterprise Linux Server - AUS 5.6 x86_64
• Red Hat Enterprise Linux Server - AUS 5.6 ia64
• Red Hat Enterprise Linux Server - AUS 5.6 i386
• Red Hat Enterprise Linux Workstation 5 x86_64
• Red Hat Enterprise Linux Workstation 5 i386
• Red Hat Enterprise Linux Desktop 5 x86_64
• Red Hat Enterprise Linux Desktop 5 i386
• Red Hat Enterprise Linux for IBM z Systems 5 s390x
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 5.6 s390x
• Red Hat Enterprise Linux for Power, big endian 5 ppc
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 5.6 ppc
• Red Hat Enterprise Linux Server from RHUI 5 x86_64
• Red Hat Enterprise Linux Server from RHUI 5 i386
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 5.6 x86_64
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 5.6 i386

Fixes

• BZ - 531697 - CVE-2009-3720 expat: buffer over-read and crash on XML with malformed UTF-8 sequences
• BZ - 632200 - CVE-2010-3493 Python: SMTP proxy RFC 2821 module DoS (uncaught exception) (Issue #9129)
• BZ - 680094 - CVE-2011-1015 python (CGIHTTPServer): CGI script source code disclosure
• BZ - 690560 - CVE-2011-1521 python (urllib, urllib2): Improper management of ftp:// and file:// URL schemes (Issue #11662)

CVEs

• CVE-2009-3720
• CVE-2010-3493
• CVE-2011-1521
• CVE-2011-1015

References

• https://access.redhat.com/security/updates/classification/#moderate