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[原创][第一阶段◇第三题]看雪论坛.腾讯公司2008软件安全技术竞赛(解答)
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发表于:
2008-10-8 19:24
2286
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[原创][第一阶段◇第三题]看雪论坛.腾讯公司2008软件安全技术竞赛(解答)
od载入后Ctrl+N查找到messageboxw函数,猜测如果函数正确则会跳转到该处,从该处开始向上跟踪,至00420D20 处,下断点:
00420D20 >/. 55 PUSH EBP ; (initial cpu selection)
00420D21 |. 8BEC MOV EBP,ESP
00420D23 |. 81EC 94000000 SUB ESP,94
00420D29 |. A1 A89D4200 MOV EAX,DWORD PTR DS:[429DA8]
00420D2E |. 33C5 XOR EAX,EBP
00420D30 |. 8945 F4 MOV DWORD PTR SS:[EBP-C],EAX
00420D33 |. 898D 6CFFFFFF MOV DWORD PTR SS:[EBP-94],ECX
00420D39 |. 66:A1 305A420>MOV AX,WORD PTR DS:[425A30]
00420D3F |. 66:8985 70FFF>MOV WORD PTR SS:[EBP-90],AX
00420D46 |. 6A 7E PUSH 7E
00420D48 |. 6A 00 PUSH 0
00420D4A |. 8D8D 72FFFFFF LEA ECX,DWORD PTR SS:[EBP-8E]
00420D50 |. 51 PUSH ECX
00420D51 |. E8 EAEFFEFF CALL <TestFloa._memset 0040fd40 f libcmt:memset.obj>
00420D56 |. 83C4 0C ADD ESP,0C
00420D59 |. DD05 C05D4200 FLD QWORD PTR DS:[425DC0]
00420D5F |. DD5D F8 FSTP QWORD PTR SS:[EBP-8]
00420D62 |. DD45 F8 FLD QWORD PTR SS:[EBP-8]
00420D65 |. DCC0 FADD ST,ST
00420D67 |. DD5D F8 FSTP QWORD PTR SS:[EBP-8]
00420D6A |. 83EC 08 SUB ESP,8
00420D6D |. DD45 F8 FLD QWORD PTR SS:[EBP-8]
00420D70 |. DD1C24 FSTP QWORD PTR SS:[ESP]
00420D73 |. 68 345A4200 PUSH TestFloa.00425A34 ; pi * 2 = %f
00420D78 |. 6A 40 PUSH 40
00420D7A |. 8D95 70FFFFFF LEA EDX,DWORD PTR SS:[EBP-90]
00420D80 |. 52 PUSH EDX
00420D81 |. E8 7CE0FEFF CALL <TestFloa.__snwprintf 0040ee02 f libcmt:snwprint.obj>
00420D86 |. 83C4 14 ADD ESP,14
00420D89 |. 6A 40 PUSH 40
00420D8B |. 68 4C5A4200 PUSH TestFloa.00425A4C ; testfloag
00420D90 |. 8D85 70FFFFFF LEA EAX,DWORD PTR SS:[EBP-90]
00420D96 |. 50 PUSH EAX
00420D97 |. 8B8D 6CFFFFFF MOV ECX,DWORD PTR SS:[EBP-94]
00420D9D |. E8 D34EFEFF CALL <TestFloa.?MessageBoxW@CWnd@@QAEHPB_W0I@Z 00405c75 f uafxcw:wincore.obj>
00420DA2 |. 8B4D F4 MOV ECX,DWORD PTR SS:[EBP-C]
00420DA5 |. 33CD XOR ECX,EBP
00420DA7 |. E8 11DFFEFF CALL <TestFloa.@__security_check_cookie@4 0040ecbd f libcmt:secchk.obj>
00420DAC |. 8BE5 MOV ESP,EBP
00420DAE |. 5D POP EBP
00420DAF \. C3 RETN
F9运行,到00420D20 处中断,F2至00420D81 处弹出错误框,得出最终出错的函数位置为00420D81 。
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