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Correctly reads 2 bytes instead of 1 byte from the SSN - previously, if the SSN was larger than 255 the incorrect SSN would be read, leading to an exception at runtime.
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Hey,
I noticed your GetSSN function was reading only the first byte (index position 4) for the SSN number - however SSNs are two bytes in length meaning if you were to make a syscall of a SSN larger than 255, you would get a runtime exception as you are calling the wrong function in the Kernel.
Demonstrated as below:
Choosing an NT function at random where SSN > 255:
You can also see it here in x64dbg:
Original call would resolve this to decimal 205 (0xcd)
However, the correct SSN for this on my current Windows build is 461 (0x1cd) - fixing the bug:
Tested with both direct and indirect syscall projects:
Direct
Indirect
Hopefully this makes sense! Happy to answer any other questions or engage further!