RHSA-2012:0474 - Security Advisory

Topic

Updated tomcat5 packages that fix two 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

Apache Tomcat is a servlet container for the Java Servlet and JavaServer
Pages (JSP) technologies.

It was found that the Java hashCode() method implementation was susceptible
to predictable hash collisions. A remote attacker could use this flaw to
cause Tomcat to use an excessive amount of CPU time by sending an HTTP
request with a large number of parameters whose names map to the same hash
value. This update introduces a limit on the number of parameters processed
per request to mitigate this issue. The default limit is 512 for
parameters and 128 for headers. These defaults can be changed by setting
the org.apache.tomcat.util.http.Parameters.MAX_COUNT and
org.apache.tomcat.util.http.MimeHeaders.MAX_COUNT system properties.
(CVE-2011-4858)

It was found that Tomcat did not handle large numbers of parameters and
large parameter values efficiently. A remote attacker could make Tomcat
use an excessive amount of CPU time by sending an HTTP request containing a
large number of parameters or large parameter values. This update
introduces limits on the number of parameters and headers processed per
request to address this issue. Refer to the CVE-2011-4858 description for
information about the org.apache.tomcat.util.http.Parameters.MAX_COUNT and
org.apache.tomcat.util.http.MimeHeaders.MAX_COUNT system properties.
(CVE-2012-0022)

Red Hat would like to thank oCERT for reporting CVE-2011-4858. oCERT
acknowledges Julian Walde and Alexander Klink as the original reporters of
CVE-2011-4858.

Users of Tomcat should upgrade to these updated packages, which correct
these issues. Tomcat must be restarted for this update to take effect.

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 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 Power, big endian 5 ppc
• Red Hat Enterprise Linux Server from RHUI 5 x86_64
• Red Hat Enterprise Linux Server from RHUI 5 i386

Fixes

• BZ - 750521 - CVE-2011-4858 tomcat: hash table collisions CPU usage DoS (oCERT-2011-003)
• BZ - 783359 - CVE-2012-0022 tomcat: large number of parameters DoS

CVEs

• CVE-2011-4858
• CVE-2012-0022

References

• https://access.redhat.com/security/updates/classification/#moderate
• http://tomcat.apache.org/security-5.html