Requirements
WinPLC7 V5 software (you can download it from [here])
A hex editor (such as HxD, Hex Workshop, etc.)
A decompiler (such as IDA Pro, OllyDbg, etc.)
Steps
Open the WinPLC7.exe file in your hex editor.
Search for the hex string "75 0A 68 00 00 00 00 E8" (without quotes).
Replace the first byte "75" with "EB" (without quotes).
Save the modified WinPLC7.exe file.
Open the WinPLC7.exe file in your decompiler.
Go to the address "0040B6F0" (without quotes).
Change the instruction "call 0040B6F5" (without quotes) to "nop" (without quotes).
Save the modified WinPLC7.exe file.
Run the WinPLC7.exe file and enjoy using WinPLC7 software without a license key.
Explanation
The hex string "75 0A 68 00 00 00 00 E8" corresponds to the assembly code "jnz short loc_40B6F5; push 0; call sub_40B6FA" (without quotes). This code is part of the license verification process of WinPLC7 software. It checks if the license key is valid, and if not, it jumps to the location "loc_40B6F5", which displays an error message and exits the program. By replacing the first byte "75" with "EB", we change the instruction "jnz short loc_40B6F5" to "jmp short loc_40B6F5", which means that it always jumps to the location "loc_40B6F5", regardless of the license key validity. However, this alone is not enough, because the location "loc_40B6F5" still displays an error message and exits the program. That's why we need to modify the instruction at the address "0040B6F0", which is "call 0040B6F5". By changing it to "nop", we make it do nothing, effectively skipping the error message and continuing the program execution. This way, we bypass the license verification process and use WinPLC7 software without a license key.
Conclusion
In this article, we have shown you how to use WinPLC7 V5 software without a license key by modifying its code. This method is simple and effective, but it may not work for future versions of WinPLC7 software. Therefore, we recommend you to purchase a legitimate license key if you want to use WinPLC7 software legally and ethically. We hope you have learned something useful from this article.
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