CWE-502
Deserialization of Untrusted Data
AI Translation Available
The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.
Status
draft
Abstraction
base
Likelihood
medium
Affected Platforms
Java
Ruby
PHP
Python
JavaScript
ICS/OT
Technical Details
AI Translation
Common Consequences
integrity
availability
other
Impacts
modify application data
unexpected state
dos: resource consumption (cpu)
varies by context
Detection Methods
automated static analysis
Potential Mitigations
Phases:
architecture and design
implementation
operation
Descriptions:
•
If available, use the signing/sealing features of the programming language to assure that deserialized data has not been tainted. For example, a hash-based message authentication code (HMAC) could be used to ensure that data has not been modified.
•
Explicitly define a final object() to prevent deserialization.
•
When deserializing data, populate a new object rather than just deserializing. The result is that the data flows through safe input validation and that the functions are safe.
•
Make fields transient to protect them from deserialization.
An attempt to serialize and then deserialize a class containing transient fields will result in NULLs where the transient data should be. This is an excellent way to prevent time, environment-based, or sensitive variables from being carried over and used improperly.
•
Employ cryptography of the data or code for protection. However, it's important to note that it would still be client-side security. This is risky because if the client is compromised then the security implemented on the client (the cryptography) can be bypassed.
•
Avoid having unnecessary types or gadgets (a sequence of instances and method invocations that can self-execute during the deserialization process, often found in libraries) available that can be leveraged for malicious ends. This limits the potential for unintended or unauthorized types and gadgets to be leveraged by the attacker. Add only acceptable classes to an allowlist. Note: new gadgets are constantly being discovered, so this alone is not a sufficient mitigation.
•
Use an application firewall that can detect attacks against this weakness. It can be beneficial in cases in which the code cannot be fixed (because it is controlled by a third party), as an emergency prevention measure while more comprehensive software assurance measures are applied, or to provide defense in depth [REF-1481].