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Encrypting a few fields
Message
De
12/02/2018 17:37:03
John Ryan
Captain-Cooker Appreciation Society
Taumata Whakatangi ..., Nouvelle Zélande
 
 
À
08/02/2018 13:26:50
Information générale
Forum:
Visual FoxPro
Catégorie:
Codage, syntaxe et commandes
Versions des environnements
Visual FoxPro:
VFP 9 SP2
OS:
Windows Server 2012 R2
Network:
Windows Server 2012 R2
Database:
Visual FoxPro
Application:
Desktop
Virtual environment:
VMWare
Divers
Thread ID:
01658009
Message ID:
01658078
Vues:
132
J'aime (1)
>>what do you mean by "hook your program" - just so I understand.

If a hacker can cause their own VFP code to run in your app- e.g. by adding a dbc Opendata event- then the entire VFP project with all its scx, prg, vcx, images etc etc can be "hooked" out of memory in seconds.

Refox XII has additional protections that block this hooking/harvesting mechanism. Defox physically alters compiled code so hooking is no longer reliable and doesn't deliver VFP source at all for fully protected code. VFP Compiler moves most of the good parts out of the project into a C++ dll, so it's no use hooking the project: now you have to decompile a dll.

The other "gotcha" is that if you use an external library for encryption, it doesn't matter which of these you use since a debugger or OLYDBG hook allows interception of the password when you make your call. This is not a VFP weakness, it's true across the board.

Ironically, the same can be said for a SQL backend that includes security if the hacker can find an entrypoint and hook your connection string.

The good news is that I've only seen two people, ever, publicly demonstrating peeling protected material out of a Refox XII. VFP Compiled or Defox-protected project. I'm one of them, and I can tell you that the knowledge required to pick out your connection strings or passwords, is well beyond most hackers.

FWIW, VFP Compiler has its own AES encryption embedded in your app but also allows you to inline C++ or ASM code in your VFP prgs to eliminate any immediately identifiable entrypoint.
"... They ne'er cared for us
yet: suffer us to famish, and their store-houses
crammed with grain; make edicts for usury, to
support usurers; repeal daily any wholesome act
established against the rich, and provide more
piercing statutes daily, to chain up and restrain
the poor. If the wars eat us not up, they will; and
there's all the love they bear us.
"
-- Shakespeare: Coriolanus, Act 1, scene 1
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