Video: PDF/XDP Malware Reversing

Since I don’t have time to write many articles, this is my first video tutorial. 🙂 This video is based on my 2016 article on cerbero-blog.com.

If you like it and want to see more, let me know!

Edit: since I was asked to share the comments in the disassembly, here’s a small snippet to add them. You can run the snippet by pressing Ctrl+Alt+R (make sure that the disassembly view is focused when running it).

from Pro.UI import proContext
from Pro.Carbon import caComment

comments = (
	(0x000000A2, "loop resolving the following APIs:\n   LoadLibraryA\n   WinExec\n   TerminateThread\n   GetTempPathA\n   VirtualProtect"),
	(0x000000C5, "calls VirtualProtect with stolen bytes"),
	(0x000000CC, "pushes URLMON string to stack"),
	(0x000000D2, "calls a gadget which calls LoadLibraryA and returns the URLMON base address"),
	(0x000000D9, "resolves URLDownloadToFileA"),
	(0x000000FB, "pushes \"regsvr32 -s \" to the stack"),
	(0x00000109, "call GetTempFilePathA"),
	(0x00000121, "appends \"wpbt0.dll\" to the path"),
	(0x00000139, "calls URLDownloadToFileA with the created path with the URL:\n   http://129.121.231.188/data/Home/w.php?f=16&e=4"),
	(0x00000143, "calls WinExec on the downloaded file"),
	(0x0000014C, "calls WinExec on \"regsvr32 -s \" followed by the downloaded file"),
	(0x00000166, "calls TerminateThread"),
)

def add_comments():
    v = proContext().getCurrentView()
    ca = v.getCarbon()
    db = ca.getDB()
    comment = caComment()
    for c in comments:
        comment.address = c[0]
        comment.text = c[1]
        db.setComment(comment)
    # update the view
    v.update()
    
add_comments()

A malware with my name

There’s a malware circulating that contains my name in its version information. I’m, of course, not the author (putting one’s own name in the version info would be brilliant). I’m clarifying, as three people already contacted me about it since yesterday.

It was probably done on purpose and it’s not the result of a random generation of different version info, as I suspect. What the author/s of this malware ignore, is that they made me stumble on an additional technique against malware, that’ll probably damage their business and force them to work more.

Given my very limited amount of spare time, it’s too soon to discuss this.