Search results
Results from the WOW.Com Content Network
The canonical heap overflow technique overwrites dynamic memory allocation linkage (such as malloc metadata) and uses the resulting pointer exchange to overwrite a program function pointer. For example, on older versions of Linux , two buffers allocated next to each other on the heap could result in the first buffer overwriting the second ...
The canonical heap overflow technique overwrites dynamic memory allocation linkage (such as malloc meta data) and uses the resulting pointer exchange to overwrite a program function pointer. Microsoft's GDI+ vulnerability in handling JPEGs is an example of the danger a heap overflow can present. [5]
Stack buffer overflow is a type of the more general programming malfunction known as buffer overflow (or buffer overrun). [1] Overfilling a buffer on the stack is more likely to derail program execution than overfilling a buffer on the heap because the stack contains the return addresses for all active function calls.
Heap sprays take advantage of the fact that on most architectures and operating systems, the start location of large heap allocations is predictable and consecutive allocations are roughly sequential. This means that the sprayed heap will roughly be in the same location each and every time the heap spray is run.
When the corrupted memory contents are used later in that program, it leads either to program crash or to strange and bizarre program behavior. Nearly 10% of application crashes on Windows systems are due to heap corruption. [1] Modern programming languages like C and C++ have powerful features of explicit memory management and pointer ...
In the example, 1 & 2 were the first to enter the circular buffer, they are the first to be removed, leaving 3 inside of the buffer. If the buffer has 7 elements, then it is completely full: A property of the circular buffer is that when it is full and a subsequent write is performed, then it starts overwriting the oldest data.
The following example, written in pseudocode, is intended to show how a memory leak can come about, and its effects, without needing any programming knowledge. The program in this case is part of some very simple software designed to control an elevator. This part of the program is run whenever anyone inside the elevator presses the button for ...
Canaries or canary words or stack cookies are known values that are placed between a buffer and control data on the stack to monitor buffer overflows. When the buffer overflows, the first data to be corrupted will usually be the canary, and a failed verification of the canary data will therefore alert of an overflow, which can then be handled, for example, by invalidating the corrupted data.