【CTF对抗-WolfCtf 2025 CrackMeExe WriteUp】此文章归类为:CTF对抗。
先查壳
UPX 壳
UPX 脱壳

IDA 看源代码,两个反调试API,x64dbg 直接Patch
IsDebuggerPresen
CheckRemoteDebuggerPresent
X64dbg 运行到IsDebuggerPresent,CheckRemoteDebuggerPresent 直接patch绕过,
运行到call rbp处发现一段shellcode
1 2 3 4 5 6 7 8 9 10 | 0000000000020000 55 48 89 E5 4D 31 D2 42 80 3C 11 00 74 05 49 FF UH.åM1ÒB.<..t.Iÿ
0000000000020010 C2 EB F4 49 83 FA 12 74 09 48 C7 C0 01 00 00 00 ÂëôI.ú.t.HÇÀ....
0000000000020020 C9 C3 68 66 6C 61 67 49 89 E3 41 53 68 59 11 00 ÉÃhflagI.ãAShY..
0000000000020030 00 48 B8 56 15 52 03 39 35 52 13 50 48 B8 11 0F .H¸V.R. 95R .PH¸..
0000000000020040 15 01 1D 2D 0F 09 50 49 89 E4 48 31 FF 49 83 FA ... - ..PI.äH1ÿI.ú
0000000000020050 00 75 05 48 89 F8 C9 C3 42 8A 5C 11 FF 48 31 D2 .u.H.øÉÃB.\.ÿH1Ò
0000000000020060 4C 89 D0 48 FF C8 49 C7 C5 04 00 00 00 49 F7 F5 L.ÐHÿÈIÇÅ....I÷õ
0000000000020070 41 8A 04 13 30 C3 48 31 C0 43 38 5C 14 FF 0F 95 A... 0 ÃH1ÀC8\.ÿ..
0000000000020080 C0 48 01 C7 49 FF CA EB C4 00 7B 00 00 00 00 00 ÀH.ÇIÿÊëÄ.{.....
0000000000020090 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
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导出来用IDA反编译,这里是加密操作,将我们输入的字符串和“flag”字符换进行异或与一串二进制进行对比

编写解密代码,输出flag。

输出flag:
wctf{Ann0y3d_Y3t?}
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