Insecure Deserialization

Insecure Deserialization occurs when an application converts serialized data, a byte stream representing an object’s state, back into an object without adequately verifying its integrity or safety. Serialization formats such as Java’s ObjectInputStream, Python’s pickle, PHP’s unserialize(), and .NET’s BinaryFormatter are commonly exploited. When an attacker can control the serialized data, they can craft malicious objects that trigger dangerous operations during the deserialization process, including remote code execution, authentication bypass, privilege escalation, and denial of service. This vulnerability gained significant attention when it was added to the OWASP Top 10 in 2017.

Why It Matters

Insecure deserialization is particularly dangerous because exploitation often leads directly to remote code execution with the privileges of the application process. Unlike injection vulnerabilities that interact with a specific subsystem (database, OS), deserialization attacks manipulate the application runtime itself. Java applications are especially susceptible due to the prevalence of “gadget chains,” sequences of existing classes that, when deserialized in a specific order, achieve arbitrary code execution. The Apache Commons Collections library gadget chain, for instance, affected thousands of Java enterprise applications.

Consider a Java web application that uses serialized objects in session cookies. An attacker who identifies this pattern can use tools like ysoserial to generate a malicious serialized object that, when the server deserializes the cookie, executes a reverse shell payload, granting the attacker direct access to the application server.

How Revaizor Handles This

Revaizor’s AI agents are trained to detect serialization markers across multiple protocols and formats, including base64-encoded Java objects, PHP serialized strings, and .NET ViewState blobs. The platform identifies deserialization sinks and tests them with format-specific payloads, safely validating whether known gadget chains are exploitable. Revaizor’s source code review capabilities complement runtime testing by identifying dangerous deserialization patterns in the codebase before they reach production environments.