|1 via 1 paths|
Find, fix and prevent vulnerabilities in your code.
- Vulnerable module: json-schema
- Introduced through: email@example.com
Introduced through: firstname.lastname@example.org › email@example.com › firstname.lastname@example.org › email@example.com › firstname.lastname@example.org
Affected versions of this package are vulnerable to Prototype Pollution via the
validate function, which when given a special payload will pollute
Object with undesired attributes.
There are two main ways in which the pollution of prototypes occurs:
- Property definition by path
Unsafe Object recursive merge
The logic of a vulnerable recursive merge function follows the following high-level model:
_proto_ defined with
Object.defineProperty() , the condition that checks if the property exists and is an object on both the target and the source passes and the merge recurses with the target, being the prototype of
Object and the source of
Object as defined by the attacker. Properties are then copied on the
Hoek are examples of libraries susceptible to recursive merge attacks.
Property definition by path
theFunction(object, path, value)
myValue is then assigned to the prototype of the class of the object.
Types of attacks
There are a few methods by which Prototype Pollution can be manipulated:
|Denial of service (DoS)||Client||This is the most likely attack.
DoS occurs when
The attacker pollutes
For example: if an attacker pollutes
|Remote Code Execution||Client||Remote code execution is generally only possible in cases where the codebase evaluates a specific attribute of an object, and then executes that evaluation.
|Property Injection||Client||The attacker pollutes properties that the codebase relies on for their informative value, including security properties such as cookies or tokens.
For example: if a codebase checks privileges for
The following environments are susceptible to a Prototype Pollution attack:
- Application server
- Web server
How to prevent
- Freeze the prototype— use
- Require schema validation of JSON input.
- Avoid using unsafe recursive merge functions.
- Consider using objects without prototypes (for example,
Object.create(null)), breaking the prototype chain and preventing pollution.
- As a best practice use
For more information on this vulnerability type:
json-schema to version 0.4.0 or higher.