Home >Backend Development >C++ >How Can I Secure My JSON Deserialization from External Sources Using Json.Net's TypeNameHandling?

How Can I Secure My JSON Deserialization from External Sources Using Json.Net's TypeNameHandling?

Linda Hamilton
Linda HamiltonOriginal
2025-01-07 14:12:40240browse

How Can I Secure My JSON Deserialization from External Sources Using Json.Net's TypeNameHandling?

External JSON Vulnerability Due to Json.Net TypeNameHandling Auto

Json.Net's TypeNameHandling auto setting can potentially introduce security risks when deserializing JSON from untrusted sources. However, these risks can be mitigated by adhering to specific guidelines.

Type Safety and Attack Gadgets

Attacks exploiting TypeNameHandling rely on constructing "attack gadgets" that execute malicious actions upon instantiation or initialization. Json.Net safeguards against these attacks by validating the compatibility of deserialized types with the expected types.

Vulnerability Conditions

While having no explicit object or dynamic members in the target class reduces the risk, it does not guarantee safety entirely. Potential vulnerabilities could arise in the following scenarios:

  • Untyped Collections: Deserializing untyped collections (e.g., List) leaves room for attack gadgets within the collection items.
  • CollectionBase Implementations: CollectionBase types can validate item types only at runtime, creating a potential vulnerability window.
  • Shared Base Types/Interfaces: Types sharing base types or interfaces with attack gadgets can inherit vulnerabilities.
  • ISerializable Interfaces: Deserialization of types implementing ISerializable may allow for untyped member deserialization.
  • Conditional Serialization: Members marked with ShouldSerializeAttribute methods can be deserialized even when not explicitly serialized.
  • Mitigating the Risk

    To minimize the risk, it is essential to follow these recommendations:

    • Use TypeNameHandling.None when possible.
    • Implement a custom SerializationBinder to validate incoming types and prevent deserialization of unexpected types.
    • Consider ignoring the [Serializable] attribute by setting DefaultContractResolver.IgnoreSerializableAttribute to true.
    • Ensure that all object members that must not be deserialized are marked with ShouldSerializeAttribute methods returning false.

    By adhering to these guidelines, it is possible to safely deserialize JSON even in the presence of TypeNameHandling auto while significantly reducing the risk of attacks.

    The above is the detailed content of How Can I Secure My JSON Deserialization from External Sources Using Json.Net's TypeNameHandling?. For more information, please follow other related articles on the PHP Chinese website!

    Statement:
    The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn