Call to Interrupt Procedure

Created the Friday 10 March 2023. Updated 6 months, 3 weeks ago.

This anti-debugging technique involves using the INT n instruction to generate a call to the interrupt or exception handler specified with the destination operand.

To implement this technique, the int 0x03 instruction is executed, followed by a ret (0xCD03, 0xC3) nested in a __try, __except block. If a debugger is present, the except block will not be executed, and the function will return TRUE, indicating that a debugger is running.

This technique can be used to prevent analysts from analyzing and manipulating the malware's code during runtime.

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The resources provided below are associated links that will give you even more detailed information and research on current evasion technique. It is important to note that, while these resources may be helpful, it is important to exercise caution when following external links. As always, be careful when clicking on links from unknown sources, as they may lead to malicious content.

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