Buffer Overflows

• Integer Overflow Vulnerabilities

  • insufficient input validation, not a buffer overflow
  • errors in integer operations may cause the integer to overflow
  • may represent the size of a packet or length of a string
  • exploits take advantage of integer overflow indirectly
  • a few actual examples.

• Stack-based Buffer Overflows

  • Buffer overflows are the result of a buffer receiving data that are larger than the allocate space.
  • Stack-based overflows are the most common because are the easiest to exploit (see the examples in the link).
  • Modern compilers (e.g. MS Visual C++ 2008) use a technique known as stack cookies to prevent use of invalid return addresses, but not enough.
  • Data Execution Prevention (DEP) of modern processors can be used to make the stack area non executable.

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