CODEWITHSUNDEEP
csecurityprintfformat-string
user9231210
user9231210

Reputation:

Format string attack, difference between %_$d and %d

I'm currently getting into binary exploitation, so far so good.

The only thing that I don't really understand is the difference between %4$d and %4d, for example. I was looking at this guide:

http://www.kroosec.com/2012/12/protostar-format2.html

and, on the last line, 'minimum field width' is mentioned while %60d is used. Is this related to my question? When should one use %$d and when %d?

Upvotes: 0

Views: 157

Answers (1)

Johannes Schidlowski
Johannes Schidlowski

Reputation: 112

The dollar sign inside a format string indicates a position of the variable used in printf. In this way, you may for example have only 1 parameter to the function, but use it 10 times in your format string, or with more parameters, in a different order. Depending on the programming language, you may or may not use mixed $ formatting.

Upvotes: 2

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