CVE-2013-6371

La funcionalidad de hash en json-c anterior a 0.12 permite a atacantes dependientes de contexto causar una denegación de servicio (consumo de CPU) a través de datos JSON manipulados, involucrando colisiones.

JSON-C implements a reference counting object model that allows you to easily construct JSON objects in C, output them as JSON-formatted strings, and parse JSON-formatted strings back into the C representation of JSON objects. Multiple buffer overflow flaws were found in the way the json-c library handled long strings in JSON documents. An attacker able to make an application using json-c parse excessively large JSON input could cause the application to crash. A denial of service flaw was found in the implementation of hash arrays in json-c. An attacker could use this flaw to make an application using json-c consume an excessive amount of CPU time by providing a specially crafted JSON document that triggers multiple hash function collisions. To mitigate this issue, json-c now uses a different hash function and randomization to reduce the chance of an attacker successfully causing intentional collisions.