The NetX Duo MQTT client leaks the packet carrying a malformed PUBLISH message. Each malformed PUBLISH costs one packet, or one chain of packets, from the network drivers receive pool, and nothing returns it. A peer that can deliver a few dozen such messages exhausts the pool and stops all inbound network traffic on the device until it is rebooted.
Weakness
The product does not sufficiently track and release allocated memory after it has been used, making the memory unavailable for reallocation and reuse.
Potential Mitigations
- Choose a language or tool that provides automatic memory management, or makes manual memory management less error-prone.
- For example, glibc in Linux provides protection against free of invalid pointers.
- When using Xcode to target OS X or iOS, enable automatic reference counting (ARC) [REF-391].
- To help correctly and consistently manage memory when programming in C++, consider using a smart pointer class such as std::auto_ptr (defined by ISO/IEC ISO/IEC 14882:2003), std::shared_ptr and std::unique_ptr (specified by an upcoming revision of the C++ standard, informally referred to as C++ 1x), or equivalent solutions such as Boost.