Easy to use debugger for Portable Executable malware

Question

I am looking for recommendations in each of the categories

• free
• charged

for easy to use debuggers fit for Portable Executable (native/non-.NET) malware analysis.

Answer 1

In the free category, Olly is the King. If you're using Win XP or older, SoftICE is fantastic as well, though finding a copy of it can be difficult these days.

In the paid category it is IDA Pro, hands down. Chris Eagle wrote an excellent book that shows you how to do advanced reverse engineering with IDA.

Also to clarify Marco, UPX can only be used to unpack exectuables that were packed with UPX in the first place. Many malware binaries exceeding modest sophistication use custom packing techniques, which cannot be reversed using UPX.