jackson-databind contains the general-purpose data-binding functionality and tree-model for Jackson Data Processor. From 2.21.0 until 2.21.4 and 3.1.4, POJOPropertiesCollector._renameProperties() allows a property with @JsonProperty(renamed) on the getter and @JsonIgnore on the setter to be renamed rather than dropped. With MapperFeature.INFER_PROPERTY_MUTATORS enabled (default), the private backing field is retained; during deserialization BeanDeserializerFactory.addBeanProps() sees hasField()==true, builds a FieldProperty, and makes the backing field writable. An attacker supplying the renamed JSON key writes the backing field directly, bypassing the @JsonIgnore on the setter. This vulnerability is fixed in 3.1.4.
Weakness
The product receives input from an upstream component that specifies multiple attributes, properties, or fields that are to be initialized or updated in an object, but it does not properly control which attributes can be modified.
Extended Description
If the object contains attributes that were only intended for internal use, then their unexpected modification could lead to a vulnerability. This weakness is sometimes known by the language-specific mechanisms that make it possible, such as mass assignment, autobinding, or object injection.
Potential Mitigations
- If available, use features of the language or framework that allow specification of allowlists of attributes or fields that are allowed to be modified. If possible, prefer allowlists over denylists.
- For applications written with Ruby on Rails, use the attr_accessible (allowlist) or attr_protected (denylist) macros in each class that may be used in mass assignment.
References
- https://github.com/FasterXML/jackson-databind/commit/c3d56dd25d52319828147c5b9aeabf2d485c250a
- https://github.com/FasterXML/jackson-databind/commit/e88cb17006b6af4883b973058f0bb6486e5074af
- https://github.com/FasterXML/jackson-databind/pull/5967
- https://github.com/FasterXML/jackson-databind/pull/5968
- https://github.com/FasterXML/jackson-databind/security/advisories/GHSA-9fxm-vc8v-hj55