Improper Access Control

Summary

An Improper Access Control vulnerability exists in Apache Commons. A special "BeanIntrospector" class was added in version 1.9.2. This can be used to stop attackers from using the "declaredClass" property of Java enum objects to get access to the class loader. However, this protection was not enabled by default. "PropertyUtilsBean" (and consequently "BeanUtilsBean") now disallows declared class-level property access by default. The fixed versions address a potential security issue when accessing enum properties in an uncontrolled way. If an application using Commons BeanUtils passes property paths from an external source directly to the "getProperty()" method of "PropertyUtilsBean", an attacker can access the enum's class loader via the "declaredClass" property available on all Java enum objects. Accessing the enum's "declaredClass" allows remote attackers to access the class loader and execute arbitrary code. The same issue exists with "PropertyUtilsBean.getNestedProperty()". In the fixed versions, a special "BeanIntrospector" suppresses the "declaredClass" property. Note that this new BeanIntrospector is enabled by default, but you can disable it to regain the old behavior; see section 2.5 of the user's guide and the unit tests. This issue affects commons-beanutils:commons-beanutils versions through 1.10.1 and org.apache.commons:commons-beanutils2 version 2.0.0-M1.