Apache Dubbo supports various rules to support configuration override or traffic routing (called routing in Dubbo). These rules are loaded into the configuration center (eg: Zookeeper, Nacos, ...) and retrieved by the customers when making a request in order to find the right endpoint. When parsing these YAML rules, Dubbo customers will use SnakeYAML library to load the rules which by default will enable calling arbitrary constructors. An attacker with access to the configuration center he will be able to poison the rule so when retrieved by the consumers, it will get RCE on all of them. This was fixed in Dubbo 2.7.13, 3.0.2

Apache Dubbo prior to 2.6.9 and 2.7.9 by default supports generic calls to arbitrary methods exposed by provider interfaces. These invocations are handled by the GenericFilter which will find the service and method specified in the first arguments of the invocation and use the Java Reflection API to make the final call. The signature for the $invoke or $invokeAsync methods is Ljava/lang/String;[Ljava/lang/String;[Ljava/lang/Object; where the first argument is the name of the method to invoke, the second one is an array with the parameter types for the method being invoked and the third one is an array with the actual call arguments. In addition, the caller also needs to set an RPC attachment specifying that the call is a generic call and how to decode the arguments. The possible values are: - true - raw.return - nativejava - bean - protobuf-json An attacker can control this RPC attachment and set it to nativejava to force the java deserialization of the byte array located in the third…

Each Apache Dubbo server will set a serialization id to tell the clients which serialization protocol it is working on. But for Dubbo versions before 2.7.8 or 2.6.9, an attacker can choose which serialization id the Provider will use by tampering with the byte preamble flags, aka, not following the server's instruction. This means that if a weak deserializer such as the Kryo and FST are somehow in code scope (e.g. if Kryo is somehow a part of a dependency), a remote unauthenticated attacker can tell the Provider to use the weak deserializer, and then proceed to exploit it.

Apache Dubbo prior to 2.7.9 support Tag routing which will enable a customer to route the request to the right server. These rules are used by the customers when making a request in order to find the right endpoint. When parsing these YAML rules, Dubbo customers may enable calling arbitrary constructors.

In Apache Dubbo prior to 2.6.9 and 2.7.9, the usage of parseURL method will lead to the bypass of white host check which can cause open redirect or SSRF vulnerability.

Apache Dubbo prior to 2.6.9 and 2.7.9 supports Script routing which will enable a customer to route the request to the right server. These rules are used by the customers when making a request in order to find the right endpoint. When parsing these rules, Dubbo customers use ScriptEngine and run the rule provided by the script which by default may enable executing arbitrary code.

A deserialization vulnerability existed in dubbo 2.7.5 and its earlier versions, which could lead to malicious code execution. Most Dubbo users use Hessian2 as the default serialization/deserialization protool, during Hessian2 deserializing the HashMap object, some functions in the classes stored in HasMap will be executed after a series of program calls, however, those special functions may cause remote command execution. For example, the hashCode() function of the EqualsBean class in rome-1.7.0.jar will cause the remotely load malicious classes and execute malicious code by constructing a malicious request. This issue was fixed in Apache Dubbo 2.6.9 and 2.7.8.

This vulnerability can affect all Dubbo users stay on version 2.7.6 or lower. An attacker can send RPC requests with unrecognized service name or method name along with some malicious parameter payloads. When the malicious parameter is deserialized, it will execute some malicious code. More details can be found below.

Unsafe deserialization occurs within a Dubbo application which has HTTP remoting enabled. An attacker may submit a POST request with a Java object in it to completely compromise a Provider instance of Apache Dubbo, if this instance enables HTTP. This issue affected Apache Dubbo 2.7.0 to 2.7.4, 2.6.0 to 2.6.7, and all 2.5.x versions.