Untrusted or Insecure Deserialization

Serialization refers to the process of converting an object into a format which can be saved to a file or a datastore, sent through streams, or sent over a network. The format in which an object is serialized can either be binary or structured text (for example, Java, XML, JSON, YAML). Deserialization reverses the serialization process, transforming serialized data coming from a file, stream, or network socket into an object.

Insecure Deserialization (aka Untrusted Deserialization) is a web application vulnerability that enables users to pass arbitrary objects or code to a deserializer. In this kind of attack, untrusted data abuses the logic of an application to inflict a denial of service (DoS) attack, achieve authentication bypass, enable remote code execution, and even execute arbitrary code as it is being deserialized.

Applications and APIs are vulnerable to Insecure Deserialization whenever they deserialize untrusted or hostile objects supplied by an attacker. A widespread vulnerability in Java environments also leave thousands of businesses seriously exposed. To protect against this vulnerability, safe deserialization is a common software development practice.