Thursday, December 17, 2009

YouTube FLV files contain unique identifiers which could be used to find who downloaded a particular file

FLV files which have been downloaded from YouTube have a unique identifier. In several files I examined, the string "sourcedata" occurs at offset 0x10E and a unique alphanumeric ID is at offsets 0x11B through 0x125. Presumably, these unique identifiers can be matched with information in YouTube logs in order to find the IP or user who downloaded the file.


Anonymous said...

I've downloaded quite a number of videos, and noticed the same thing, but they are all different.

I'm actually thinking there is a way to identify the server or the video itself.

Boris Gjenero said...

If I download the same video multiple times from the same server, the identifier is always different. This seems to imply that the identifier can be used to identify a particular download.

Anonymous said...

The field contains (among other things) the time of the (start of the) download in time_t format (seconds after 1/1/1970). I haven't been able yet to hack the other parts of the string (28 bytes usually).