Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')
In Apache Synapse, by default no authentication is required for Java Remote Method Invocation (RMI). Apache Synapse versions prior to 3.0.1 allow Remote Code Execution attacks that can be performed by Injecting specially crafted serialized objects. And the presence of Apache Commons Collections 3.2.1 (commons-collections-3.2.1.jar) or previous versions in Synapse distribution makes this exploitable. To mitigate the issue, we need to limit RMI access to trusted users only. In Synapse 3.0.1, Commons Collection has been updated to 3.2.2 version.
CWE-74 - Injection
Listed as the number one web application security risk on the 'OWASP Top Ten', injection attacks are widespread and dangerous, especially in legacy applications. Injection attacks are a class of vulnerabilities in which an attacker injects untrusted data into a web application that gets processed by an interpreter, altering the program's execution. This can result in data loss/theft, loss of data integrity, denial of service, and even compromising the entire system.