Question about hacking an old dos program

[Doomer]

This is an ancient DOS DB app written in gawd only knows what. It's not a commercial app. The guy who wrote it is dead.

It contains a time bomb that will kill it at midnight on Jan. 5th. I'm trying to figure out a way to defuse it. It also has code that detects if the clock has been set back so that's not an option.

Anybody know how this might have been done and if there is any way to defuse it? I don't have the source code so that's out.

 

[imported_FishTaco]

Have you tested it on a different machine? How do you know it's got a time bomb it it? Did the guy die while you were torturing him for the code to defuse the time bomb? Do you work for the CIA?

 

[Doomer]

LOL, it dies every year without a reg code to enter at the proper time. They were paying this guy but now that he's dead, that option is out and there seems to be no one else who knows anything about it. Including how to get a new reg code.

 

[DaveSimmons]

3 options (besides building a new, equivalent app):

- crack the reg key algorithm (by looking at old valid codes or de-compiling the program)

- hack the code to disable license checking

- use a hardware or kernel debugger (Soft-ICE etc) and step through the code for entering the reg code or the code doing the license check later. Chances are one or both build the correct license string and then compare it to the one that you entered.

I've never had a reason to do any of these so I can't offer any more suggestions.

 

[EagleKeeper]

Fourth Option:

Determine the specs and functionality of the program and get it replaced with one that you control the source code to and/or has no time bombs in it. IF you can get your hands on the original source code, so much the better.

This may not be free or inexpensive (depending on the application), however, it will allow you complete control and peace of mind over the application.

Look at the time lost trying to resolve this problem and what can happen if the app needs to bew enhanced for any reason.

/edit (option also added by Dave above)

 

[talyn00]

disassembler, it'd be tedious, probably would be easier to just write a new program