Buffer over-read

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In computer security and programming, a buffer over-read[1] is an anomaly where a program, while reading data from a buffer, overruns the buffer's boundary and reads (or tries to read) adjacent memory. This is a special case of violation of memory safety.

Buffer over-reads can be triggered, as in the Heartbleed bug, by maliciously crafted inputs that are designed to exploit a lack of bounds checking to read parts of memory not intended to be accessible. They may also be caused by programming errors alone. They can result in erratic program behavior, including memory access errors, incorrect results, a crash, or a breach of system security. Thus, they are the basis of many software vulnerabilities and can be maliciously exploited to access privileged information.

Programming languages commonly associated with buffer over-reads include C and C++, which provide no built-in protection against using pointers to access data in any part of virtual memory, and which do not automatically check that reading data from a block of memory is safe; respective examples are attempting to read more elements than contained in an array, or failing to append a trailing terminator to a null-terminated string. Bounds checking can prevent buffer over-reads,[2] while fuzz testing can help detect them.

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  1. ^ "CWE – CWE-126: Buffer Over-read (2.6)". Cwe.mitre.org. February 18, 2014. Retrieved April 10, 2014. 
  2. ^ Yves Younan; Wouter Joosen; Frank Piessens (2013-02-25). "Efficient protection against heap-based buffer overflows without resorting to magic" (PDF). Dept. of Computer Science, Katholieke Universiteit Leuven. Retrieved 2014-04-24. 

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