Insecure Deserialization

Overview

Insecure deserialization is a vulnerability that can be exploited by attackers to gain unauthorized access to a web application or execute remote code. It occurs when serialized objects, which are converted byte strings, are not properly validated during deserialization, allowing malicious actors to modify the objects and potentially compromise the application.

Description

Insecure deserialization poses a significant risk to web applications as it enables attackers to manipulate serialized objects and execute arbitrary code on the server. This vulnerability can lead to various types of attacks, such as remote code execution, privilege escalation, and data tampering. To prevent insecure deserialization, developers need to implement proper security measures and follow best practices.

How to Prevent ?

To protect your web application from insecure deserialization, it is crucial to implement the following security measures: 1. Avoid accepting serialized objects from untrusted sources whenever possible. 2. Implement integrity checks, such as digital signatures, on serialized objects to prevent hostile object creation or data tampering. 3. Enforce strict type constraints during deserialization to ensure that the code only expects a specific set of classes. 4. Run deserialization code in low privilege environments or isolated containers to minimize the impact of potential attacks. 5. Log deserialization exceptions and failures, such as unexpected types or thrown exceptions, to identify potential security risks. 6. Restrict or monitor network connectivity from servers or containers responsible for deserialization. 7. Monitor deserialization activities and consider setting up alerts for suspicious or constant deserialization attempts.

Example Attack Scenarios:

• Example Attack Scenario #1:  A React application utilizes Spring Boot microservices and serializes user state to pass it between requests. An attacker identifies the serialized object and exploits it using a tool like Java Serial Killer to gain remote code execution on the application server.

• Example Attack Scenario #2:  A PHP forum relies on PHP object serialization to store user information, including user ID, role, and password hash. An attacker modifies the serialized object to grant themselves admin privileges, compromising the entire web application.