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Sleeping DLL beauties

February 4, 2020 in Random ideas, Silly, Undocumented Windows Internals

How do we sleep?

We do one of these:

  • kernel32/kernelbase ! Sleep
  • kernel32/kernelbase ! SleepEx
  • ntdll ! ZwDelayExecution

but… not only.

Windows 10 offers more libs with more sleeping goodness:

  • staterepository.core.dll ! sqlite3_win32_sleep
  • winsqlite3.dll ! sqlite3_win32_sleep
  • number of tools e.g. Visual Studio offer access to e_sqlite3.dll ! sqlite3_win32_sleep, Python to sqlite3.dll ! sqlite3_win32_sleep

These are actually identical SQLite functions exported by various libraries.

And then you may have LibreSSL on your system (c:\windows\system32\libcrypto.dll), so you can use:

  • libcrypto.dll, sleep

All of them can be used as a lame anti-sandbox/anti-analysis alternative to traditional delay functions listed at the top of the post. And as a random, but lasting very long delay replacing a never ending loop in batch files, or if lucky, maybe even ping


By executing these APIs via rundll32:

  • start /wait rundll32 kernel32.dll, Sleep
  • start /wait rundll32 kernelbase.dll, Sleep
  • start /wait rundll32 kernel32.dll, SleepEx
  • start /wait rundll32 kernelbase.dll, SleepEx
  • start /wait rundll32 staterepository.core.dll, sqlite3_win32_sleep
  • start /wait rundll32 winsqlite3.dll, sqlite3_win32_sleep
  • start /wait rundll32 sqlite3.dll, sqlite3_win32_sleep
  • start /wait rundll32 e_sqlite3.dll, sqlite3_win32_sleep
  • start /wait rundll32 libcrypto.dll, sleep

In these cases the argument to functions will be pretty high numbers (taken from stack and kinda random), but it’s not about logic, is it? 😉

Batch decompilation with IDA / Hex-Rays Decompiler

July 4, 2019 in IDA/Hex-Rays, Random ideas, Reversing, Silly, Tips & Tricks, Trivia

if you are very used to 32-bit IDA you may sometimes find yourself in a blind alley when you try to port your working solution to IDA 64-bit. This was the case with my old batch decompilation script.

The way it works is very simple – for every <file> in a folder, run IDA in its automation/batch mode mode, decompile the <file>, and finally save it in a <file>.c file – more or less like the below (I am omitting the loop):

c:\Ida\idaw.exe -A -Ohexrays:-new:%%k.c:ALL “%%k”

Nothing could be simpler.

Until you run it with the 64-bit idaw64.exe:

c:\Ida\idaw64.exe -A -Ohexrays:-new:%%k.c:ALL “%%k”

It doesn’t work. It loads idaw64 and just stays there.

The gotcha is in a plug-in name. The 64-bit decompiler’s plugin name is not hexrays, it’s not hexrays64 either. It is actually hexx64.dll.

So, you have to run this instead:

c:\Ida\idaw64.exe -A -Ohexx64:-new:%%k.c:ALL “%%k”

It’s ridiculously trivial, but it’s always the little things.

Also, interestingly, when you google hexx64.dll or hexx64.p64 you only get a few hits. As if not too many ppl ever came across the issue.

Another gotcha is that if you run it with too many files, your system’s performance will deteriorate quickly. I don’t know if it is memory fragmentation/leaks, or something else, but after running the script on a number of samples I observed my VM dying on me and requiring a restart due to low memory (despite no other process running on a 2G RAM guest). If you know what causes it I would be grateful if you could let me know.

The third gotcha is to rely on the text version of IDA for this task – it is faster than the GUI version. At least in my experience.

Finally, the last gotcha is to remove all the other plugins from the IDA’s Plugins directory, other than the one you are using e.g. hexrays. Why? This may look like nothing, but IDA enumerates and loads all of them _each_ time it starts.