
Vulnerable to this kind of attack, as showed below:įollowing are some examples of Format Functions, which if not treated,Ĭan expose the application to the Format String Attack. Username inserted in some fields of the page, the website could be For example, if the printf function is used to print the Vulnerability by inserting formatting characters in a form of the If the application uses Format Functions in the source-code, which isĪble to interpret formatting characters, the attacker could explore the In this way, it is possible to define a well-crafted input that couldĬhange the behavior of the format function, permitting the attacker toĬause denial of service or to execute arbitrary commands. However, the Format Function is expecting moreĪrguments as input, and if these arguments are not supplied, the Parsed by the Format Function, and the conversion specified in the Parameter, like %x, is inserted into the posted data, the string is The attack could be executed when the application doesn’t properly


The Format Function is an ANSI C conversion function, like.To understand the attack, it’s necessary to understand the components

In this way, theĪttacker could execute code, read the stack, or cause a segmentationįault in the running application, causing new behaviors that couldĬompromise the security or the stability of the system. String is evaluated as a command by the application. The Format String exploit occurs when the submitted data of an input
