Despite previous efforts in auditing software manually and automatically, buffer overruns are still being discovered in programs in use. A dynamic bounds checker detects buffer overruns in erroneous software before it occurs and thereby prevents attacks from corrupting the integrity of the system. Dynamic buffer overrun detectors have not been adopted widely because they either (1) cannot guard against all buffer overrun attacks, (2) break existing code, or (3) incur too high an overhead. This paper presents a practical detector called CRED (C Range Error Detector) that avoids each of these deficiencies. CRED finds all buffer overrun attacks as it directly checks for the bounds of memory accesses. Unlike the original referent-object based bounds-checking technique, CRED does not break existing code because it uses a novel solution to support program manipulation of out-of-bounds addresses. Finally, by restricting the bounds checks to strings in a program, CRED’s overhead is greatly reduced without sacrificing protection in the experiments we performed. CRED is implemented as an extension of the GNU C compiler version 3.3.1. The simplicity of our design makes possible a robust implementation that has been tested on over 20 open-source programs, comprising over 1.2 million lines of C code. CRED proved effective in detecting buffer overrun attacks on programs with known vulnerabilities, and is the only tool found to guard against a testbed of 20 different buffer overflow attacks[34]. Finding overruns only on strings impose an overhead of less

The size and complexity of software systems is growing, increasing the number of bugs. Many of these bugs constitute security vulnerabilities. Most common of these bugs is the buffer overflow vulnerability. In this paper we implement a testbed of 20 different buffer overflow attacks, and use it to compare four publicly available tools for dynamic intrusion prevention aiming to stop buffer overflows. The tools are compared empirically and theoretically. The best tool is effective against only 50 % of the attacks and there are six attack forms which none of the tools can handle.

Many remote attacks against computer systems inject binary code into the execution path of a running program, gaining control of the program's behavior. If each defended system or program could use a machine instruction set that was both unique and private, such binary code injection attacks would become extremely difficult if not impossible. A binary-to-binary translator provides an economic and flexible implementation path for realizing that idea. As a proof of concept, we describe a randomized instruction set emulator (RISE) based on the open-source Valgrind x86-to-x86 binary translator. Although currently very slow and memory-intensive, our prototype RISE can indeed disrupt binary code injection attacks against a program without requiring its recompilation, linking, or access to source code. We describe the RISE implementation, give evidence demonstrating that RISE defeats common attacks, consider consequences of the dense x86 instruction set on the method's effects, and discuss limitations of the RISE prototype as well as design tradeoffs and extensions of the underlying idea.