Insecure Deserialization
TLDR: Insecure deserialization occurs when untrusted data is deserialized, allowing attackers to manipulate serialized objects to execute malicious actions. This vulnerability, first highlighted in the early 2000s with the rise of object-oriented programming, can lead to remote code execution (RCE), data tampering, or unauthorized access to sensitive resources.
https://owasp.org/www-community/vulnerabilities/Insecure_Deserialization
Deserialization transforms serialized data back into an object, enabling applications to reconstruct complex data structures. However, if the input is not validated, attackers can exploit this process to introduce harmful objects or override existing ones. Common targets include applications written in Java, Python, or PHP, where serialization frameworks like Java Serialization API or pickle are frequently used.
https://owasp.org/www-community/Serialization_and_Deserialization
Insecure deserialization vulnerabilities often arise from poorly implemented or misconfigured serialization frameworks. For instance, using default settings that accept all object types without validation increases the risk of injecting malicious payloads. Employing allowlists or explicitly defining permissible classes during deserialization mitigates this risk.
https://owasp.org/www-community/Input_Validation
Attack scenarios include crafting serialized payloads that execute arbitrary code or escalate privileges within the application. A notorious example is the Apache Commons Collections vulnerability discovered in 2015, where maliciously crafted payloads exploited a deserialization flaw to achieve RCE. Addressing such risks involves patching vulnerable libraries and implementing secure serialization practices.
https://commons.apache.org/proper/commons-collections/
Preventing insecure deserialization also requires a combination of defensive measures, including input sanitization, encryption of serialized data, and sandboxing deserialization processes. Organizations should regularly audit their codebases, libraries, and serialization settings to minimize attack surfaces and align with security best practices.