Isn't this "DLL hijacking" thing a bit overblown? The directory an application runs from on Windows has always been considered part of the security perimeter of the application.
If you can drop a malicious DLL where putty.exe lives, can't you just drop a malicious putty.exe?
If you can drop a malicious DLL where putty.exe lives, can't you just drop a malicious putty.exe?