[Snort-sigs] byte_test and buffer cursor

Alex McDonnell amcdonnell at ...435...
Thu Feb 9 16:34:23 EST 2017


I'm pretty sure that's in the Snort Manual, byte_test does not move the
cursor, byte_extract does. You could also test for the value you expect in
your second test to verify ;)

Alex McDonnell
TALOS

On Thu, Feb 9, 2017 at 4:30 PM, Y M <snort at ...3751...> wrote:

> Does a byte_test move the cursor into a buffer the number of bytes it
> tests? Does is depend on the buffer against which the byte_test is
> operating?
>
>
> In essence, I am trying to use byte_test to validate that the decimal
> value of X number of bytes fall within a decimal range. Something similar
> to:
>
>
> http_raw_header; byte_test:3,>,160,0,relative;
> byte_test:3,<,170,0,relative;
>
>
> If the first byte_test above moves the cursor 3 bytes into the buffer, how
> can I reset the cursor back to the beginning of the buffer of the
> last/relative content match (http_raw_header)? Or am I just doing it all
> wrong?
>
>
> YM
>
>
>
>
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