RHSA-2017:0527 - Security Advisory

Topic

An update for tomcat6 is now available for Red Hat Enterprise Linux 6.

Red Hat Product Security has rated this update as having a security impact of Moderate. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.

Description

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

Security Fix(es):

• It was discovered that the code that parsed the HTTP request line permitted invalid characters. This could be exploited, in conjunction with a proxy that also permitted the invalid characters but with a different interpretation, to inject data into the HTTP response. By manipulating the HTTP response the attacker could poison a web-cache, perform an XSS attack, or obtain sensitive information from requests other then their own. (CVE-2016-6816)

Note: This fix causes Tomcat to respond with an HTTP 400 Bad Request error when request contains characters that are not permitted by the HTTP specification to appear not encoded, even though they were previously accepted. The newly introduced system property tomcat.util.http.parser.HttpParser.requestTargetAllow can be used to configure Tomcat to accept curly braces ({ and }) and the pipe symbol (|) in not encoded form, as these are often used in URLs without being properly encoded.

• A bug was discovered in the error handling of the send file code for the NIO HTTP connector. This led to the current Processor object being added to the Processor cache multiple times allowing information leakage between requests including, and not limited to, session ID and the response body. (CVE-2016-8745)

Solution

For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

Affected Products

• Red Hat Enterprise Linux Server 6 x86_64
• Red Hat Enterprise Linux Server 6 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 i386
• Red Hat Enterprise Linux Workstation 6 x86_64
• Red Hat Enterprise Linux Workstation 6 i386
• Red Hat Enterprise Linux Desktop 6 x86_64
• Red Hat Enterprise Linux Desktop 6 i386
• Red Hat Enterprise Linux for IBM z Systems 6 s390x
• Red Hat Enterprise Linux for Power, big endian 6 ppc64
• Red Hat Enterprise Linux for Scientific Computing 6 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support (for IBM z Systems) 6 s390x

Fixes

• BZ - 1397484 - CVE-2016-6816 tomcat: HTTP Request smuggling vulnerability due to permitting invalid character in HTTP requests
• BZ - 1403824 - CVE-2016-8745 tomcat: information disclosure due to incorrect Processor sharing

CVEs

• CVE-2016-6816
• CVE-2016-8745

References

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