Deserialization of Untrusted Data vulnerability in Apache ShardingSphere-Agent, which allows attackers to execute arbitrary code by constructing a special YAML configuration file.
The attacker needs to have permission to modify the ShardingSphere Agent YAML configuration file on the target machine, and the target machine can access the URL with the arbitrary code JAR. An attacker can use SnakeYAML to deserialize java.net.URLClassLoader and make it load a JAR from a specified URL, and then deserialize javax.script.ScriptEngineManager to load code using that ClassLoader. When the ShardingSphere JVM process starts and uses the ShardingSphere-Agent, the arbitrary code specified by the attacker will be executed during the deserialization of the YAML configuration file by the Agent.
This issue affects ShardingSphere-Agent: through 5.3.2. This vulnerability is fixed in Apache ShardingSphere 5.4.0.
The product deserializes untrusted data without sufficiently verifying that the resulting data will be valid.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Shardingsphere | Apache | * | 5.4.0 (excluding) |
It is often convenient to serialize objects for communication or to save them for later use. However, deserialized data or code can often be modified without using the provided accessor functions if it does not use cryptography to protect itself. Furthermore, any cryptography would still be client-side security – which is a dangerous security assumption. Data that is untrusted can not be trusted to be well-formed. When developers place no restrictions on “gadget chains,” or series of instances and method invocations that can self-execute during the deserialization process (i.e., before the object is returned to the caller), it is sometimes possible for attackers to leverage them to perform unauthorized actions, like generating a shell.