I received an email from a friend recently, asking about finding an Event Log in unallocated (ne "free") space. He mentioned that he'd found it using a hex editor and copied it out of the image to a separate file, but still couldn't open it in the Event Viewer.

That got me thinking about the content of my book, and how that could be useful in a situation like this. On page 201 of Windows Forensic Analysis, table 5.3 lists the event record structure; that is, what an event record "looks like". With this information alone, event records can be retrieved from unallocated space; once you find the "magic number", back up 4 bytes and you've got the size of the event record. From there, you can copy out the entire event record and the rest of the information within the record can be easily parsed from unallocated space, or even from the pagefile or a RAM dump.

A post from another forum got me thinking that the same is true for Registry keys, as well. Figure 4.3 illustrates a hex view of what a Registry key and a Registry value "look like" on disk. Using this information, as well as the code listed on pgs. 133 and 134, Registry keys and values can be extracted and reconstructed from unallocated space, the pagefile, or even a RAM dump.

The great thing is that event records and Registry keys have time stamps associated with them (Registry values do not). This also illustrates what can be retrieved from these other areas through data carving...after all, event records and Registry structures have "magic numbers", similar to file headers, and their data can be carved out just as easily.