Information, Computer and Network Security Terms Glossary and Dictionary

Format String Attack

Format String Attacks are caused from the use of unfiltered user input as the format string parameter in certain C functions that perform formatting, such as printf(). A malicious user may use the %s and %x format tokens, among others, to print data from the stack or possibly other locations in memory. One may also write arbitrary data to arbitrary locations using the %n format token, which commands printf() and similar functions to write back the number of bytes formatted to an argument of type int *. By manipulating the stack by using spurious format tokens, this argument can be faked as part of the format string.

Related Terms

Format String Attack