I understand that encrypting files in CTR mode is not perfectly safe, because it potentially leaves the files open for cryptanalysis, if the attacker has access to previous versions of the same files. But is this really feasible when we are talking about encrypting files?
Lets say we got a program that reads and writes encrypted files with AES CTR mode. If we have a word document it will be written to many times, and therefore change alot without the key and counter changing for specific blocks.
Now how feasible is it really for an attacker to actually find these previous versions on a given harddisk? Should this constellation not be reasonable secure against anyone except maybe the NSA?