CVE-2011-2526: Improper Input Validation in Apache Tomcat
Summary
CVE-2011-2526: Improper Input Validation in Apache Tomcat. Affects org.apache.tomcat:tomcat across 3 version ranges.
< 5.5.34
>= 6.0.0, < 6.0.33
>= 7.0.0, < 7.0.19
Fixed in 5.5.34, 6.0.33 or 7.0.19, depending on the release line you run. How to fix ↓
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Background
Apache Tomcat is an open-source web server and servlet container that is used to deploy Java-based web applications. It provides a Java HTTP web server environment for running Java code. The vulnerability identified as CVE-2011-2526 affects Apache Tomcat versions 5.5.x, 6.x, and 7.x. This vulnerability arises when the sendfile feature is enabled for the HTTP APR or HTTP NIO connector. It allows local users to bypass file access restrictions or cause a denial of service by exploiting an untrusted web application.
Vulnerability Detail
The vulnerability in Apache Tomcat arises due to improper input validation. When the sendfile feature is enabled for the HTTP APR or HTTP NIO connector, certain request attributes are not properly validated. This allows local users to bypass intended file access restrictions or cause a denial of service. An attacker can leverage an untrusted web application to exploit this vulnerability. The consequences of this vulnerability include unauthorized access to files and directories, as well as potential crashes or infinite loops in the JVM.
How To Fix
Fixed versions by release line
The minimum fixed version depends on the release line you run.
-
< 5.5.345.5.34 -
>= 6.0.0, < 6.0.336.0.33 -
>= 7.0.0, < 7.0.197.0.19
Tip — Not sure which release line you're on? Vulert can find the fix for the version you are using. Scan free →
Workaround
If upgrading to a fixed version is not immediately feasible, a workaround can be implemented by disabling the sendfile feature for the HTTP APR or HTTP NIO connector. This can be achieved by modifying the Tomcat configuration file and setting the 'enableSendfile' attribute to 'false'. By disabling the sendfile feature, the vulnerability can be mitigated until a proper upgrade can be performed. Here is an example of how to disable the sendfile feature in the Tomcat configuration file:
<Connector port="8080" protocol="HTTP/1.1" connectionTimeout="20000" redirectPort="8443" enableSendfile="false" />
Conclusion
The vulnerability identified as CVE-2011-2526 in Apache Tomcat can be mitigated by upgrading to the fixed versions of the software. By addressing the improper input validation issue, the risk of unauthorized file access and denial of service can be minimized. For further support and assistance in vulnerability remediation, please contact DevNack.com.
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FAQ
Apache Tomcat is an open-source web server and servlet container that is used to deploy Java-based web applications. It provides a Java HTTP web server environment for running Java code.
The vulnerability affects Apache Tomcat versions 5.5.x, 6.x, and 7.x.
This vulnerability can be exploited by leveraging an untrusted web application. By bypassing file access restrictions or causing a denial of service, an attacker can gain unauthorized access to files and directories or crash the JVM.
The potential consequences of this vulnerability include unauthorized access to files and directories, as well as potential crashes or infinite loops in the JVM.
To fix this vulnerability, it is recommended to upgrade to a fixed version of Apache Tomcat. For version 5.5.x, upgrade to version 5.5.34 or later. For version 6.x, upgrade to version 6.0.33 or later. For version 7.x, upgrade to version 7.0.19 or later.
References
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