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Duster is the Dead\/Uninitialized Stack Eraser, an injectable DLL that causes uninitialized stack and heap memory in its host process to be wiped over with a specific value. It is intended as a crude tool to assist in the run-time discovery of uninitialized memory usage problems by increasing the chances that the host process will raise an exception when a value in uninitialized memory is used. To use Duster, just inject it into the target process (using the DLLInject utility), or add it to AppInit_DLLs (possible but not recommended).<\/p>\n
Duster is a quick and dirty implementation of its concept, and as such, it has a number of limitations:<\/p>\n
Stack wiping is accomplished by overwriting all memory between the stack commit “ceiling” and ESP, whenever RtlAllocateHeap, RtlReAllocateHeap, or RtlFreeHeap is called, an exception occurs, or a system call is dispatched, which seriously limits the execution flow “granularity” with which stack wiping occurs. Additionally, system call dispatch hooking is accomplished by replacing specific “INT 2Eh” or “MOV EDX, 7FFE0300h” instructions, the first of which currently relies upon a two-byte privileged instruction which is handled specially by the exception handler hook, resulting in some overhead but mostly making it difficult to use a debugger in conjunction with Duster on Windows 2000.<\/p>\n
Heap wiping, in addition to a limited amount of heap and argument validation, is performed whenever a heap block is allocated or freed. This is roughly a subset of the functionality provided by the Windows heap manager in debug mode, with the most significant deficiency on Duster’s part being that it does not wipe memory following a call to RtlReAllocateHeap.<\/p>\n
You can download here:<\/p>\n
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