CrackMe® Practices for Newbies ~ Moderated

A bit of explanation
Thursday, 21-Jan-99 11:44:11
    195.184.226.121 writes:

    Hi Pedro,

    I think you have found the calculation area... 8) (Yahoo!!!)

    I ran through it a few times and I think I know what some parts do... I've added a bit of comments to what you typed...

    CALL MSVBVM50!__vbaLenBstr
    IMUL EAX,EAX,0000029A <--Length of what you entered mulitple by 666
    MOV [EBP-009C],EAX
    PUSH DWORD PTR [EBP-18]
    FILD DWORD PTR [EBP-009C] <--load result into floating point...
    FDIV REAL8 PTR [00401060] <--divide by 8
    FDIV REAL8 PTR [00401068] <--divide by 60
    FSUB REAL8 PTR [00401070] <--add 2 (should be subtract -2)
    FSUB REAL8 PTR [00401078] <--subtract 0.375
    FSTP REAL8 PTR [0041403C] <--store result?
    FLD REAL8 PTR [EBP-20]
    FDIV REAL8 PTR [00401080]
    FMUL REAL8 PTR [00401088]
    FSTP REAL8 PTR [00414044]
    CALL MSVMVB50!__vbaLenBstr
    IMUL EAX,EAX,0000014D <--Length of what you entered mulitple by 333
    MOV [EBP-00A0],EAX
    FILD DWORD PTR [EBP-00A0] <--load result into floating point...
    FDIV REAL8 PTR [00401060] <--divide by 8
    FDIV REAL8 PTR [00401068] <--divide by 60
    FSUB REAL8 PTR [00401070] <--add 2 (should be subtract -2)
    FSUB REAL8 PTR [00401078] <--subtract 0.375
    FSUB REAL8 PTR [00401090] <--subtract 0.8375
    FSTP REAL8 PTR [0041404C] <--store result?
    FLD REAL8 PTR [00414044]
    FCOMP REAL8 PTR [00401098] <-- 401098 = 72... so maybe something compared with 72
    FSTSW AX
    SAHF
    JNZ 004133B2 Change this to JZ...

    For all the F commands, ignore the Fs and you will more or less know what it means... to see all the 0.375, 0.8375 values, make sure your data window is showing Long values... by typing "d L" minus quote. To see values after the math, make sure floating point stack window is on by typing "wf" and if it is not showing ST(0) etc, type "wf f"


    Bye!


    EB


Message thread:

Pedros Thread (n/t) (21-Jan-99 06:26:03)

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