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by z92 2028 days ago
Here's the summary on how he did it :

- Search and list all FLV files on the disk.

- Search for all FLV file signatures on raw disk.

- For each known file on the disk, compute md5 of the first 512 bytes.

- For each FLV file signature found on raw disk exclude those that match any of the known files using those md5 values.

- That leads to only 5 files remaining.

- The original file was known to be 1.6 GB. Read 1.8 GB serially from raw disk starting from file signature and save those.

- One of these is your file.

That will work if your file isn't fragmented on the disk, I guess.

1 comments

If anyone would like to read more, this technique is called "file carving".

> That will work if your file isn't fragmented on the disk, I guess.

Even 15 years ago when I was doing digital forensics it was actually pretty uncommon to have to deal with fragmentation. After about 2000 filesystem allocation implementations started avoiding it like the plague.

It is hard to avoid it when streaming a video of unknown length to disk though.

And as soon as you start to fill up your volume fragmentation will spread quickly.