MFC == Microsoft Foundation Class,微软基础类库,他封装了Windows API以便用户更快速的开发界面功能程序 然而该库及其庞大而复杂,需要有C++的功底否则很难解决bug,逆向起来也是需要一定技巧。 本人曾总结过Windows消息大全,他截取自winuser.h commctrl.h,如果将这些消息以及通知码(LVN_??这样的)总结一下,对分析很有好处: #define WM_NULL 0x0000 0 #define WM_CREATE 0x0001 #define WM_DESTROY 0x0002 #define WM_MOVE 0x0003 #define WM_SIZE 0x0005 #define WM_ACTIVATE 0x0006 #define WM_SETFOCUS 0x0007 #define WM_KILLFOCUS 0x0008 #define WM_ENABLE 0x000A #define WM_SETREDRAW 0x000B #define WM_SETTEXT 0x000C #define WM_GETTEXT 0x000D #define WM_GETTEXTLENGTH 0x000E #define WM_PAINT 0x000F 。。。。。。。。。。。。。。。
如果拿其他自己写的程序来说明显然没有说服力,我们就找一个MFC写的来看,超凡搜索BeyondSeacher ,下载下来以后主程序是P2P Searcher.exe,网上说他们抄袭了amule的,我们就来看看究竟。用peid看做初步判断,可以看到Microsoft Visual C++ 7.0 [Debug] IDA载入,先来找入口点,Start->WinMain->可以看到了IDA识别出了Afx系内部函数,且为静态调用。对于对话框类MFC程序,C??App和C???Dlg是关键类,在源码中可以看到这一点,总是有个全局对象,例如“CtestmfcApp theApp;”,那么就需要在c库_initc()中进行初始化(__xc_a -> __xc_z),另外C???App构造的时候会先构造父类CWinApp,且构造父类之后会设置设置虚表从而构造子类,C???Dlg过程类似。根据该原理可以定位到这2个类的位置。先找到CWinApp::CWinApp构造函数,发现索引位置 void *__thiscall sub_401850(void *this) { void *v1; // esi@1
v1 = this; CWinApp::CWinApp(this, 0); *(_DWORD *)v1 = &off_4315F8; return v1; } 显然是C???App的构造函数,先不急着看,往上层找: int sub_42FF70() { sub_401850(&unk_43F0E0); return atexit(sub_42FFF0); } 可见此处执行的是c库,程序启动时构造C???App myapp,同时注册退出时的析构函数,以便清理资源 在往上看已经是一堆要在启动时要初始化的函数了。。。 .data:0043D000 _data segment para public 'DATA' use32 .data:0043D000 assume cs:_data .data:0043D000 ;org 43D000h .data:0043D000 dword_43D000 dd 0 ; DATA XREF: HEADER:0040025Co .data:0043D000 ; __cinit+45o .data:0043D004 dd offset ___security_init_cookie .data:0043D008 dd offset sub_42C50E .data:0043D00C dd offset sub_42C51A .data:0043D010 dd offset sub_4275B5 .data:0043D014 dd offset sub_42D447 .data:0043D018 dd offset sub_42FFB2 .data:0043D01C dd offset unknown_libname_372 ; MFC 3.1-11.0 32bit .data:0043D020 dd offset sub_42FF70 .data:0043D024 dd offset sub_42FF90 .data:0043D028 dd offset sub_42FFA6 .data:0043D02C dd offset unknown_libname_239 ; MFC 3.1-11.0 32bit .data:0043D030 dd offset unknown_libname_240 ; MFC 3.1-11.0 32bit .data:0043D034 dd offset unknown_libname_241 ; MFC 3.1-11.0 32bit .data:0043D038 dd offset sub_4269DB 。。。。。。。。。。
接着看sub_401850,其虚表为off_4315F8: .rdata:004315F8 off_4315F8 dd offset sub_42B312 ; DATA XREF: sub_401850+Ao .rdata:004315FC dd offset sub_401970 .rdata:00431600 dd offset nullsub_4 .rdata:00431604 dd offset ?OnCmdMsg@CCmdTarget@@UAEHIHPAXPAUAFX_CMDHANDLERINFO@@@Z ; CCmdTarget::OnCmdMsg(uint,int,void *,AFX_CMDHANDLERINFO *) .rdata:00431608 dd offset ?OnFinalRelease@CCmdTarget@@UAEXXZ ; CCmdTarget::OnFinalRelease(void) .rdata:0043160C dd offset sub_4229A6 .rdata:00431610 dd offset ?_Get_deleter@_Ref_count_base@std@@UBEPAXABVtype_info@@@Z_6 ; std::_Ref_count_base::_Get_deleter(type_info const &) .rdata:00431614 dd offset sub_4229AC .rdata:00431618 dd offset sub_4229AC .rdata:0043161C dd offset ?GetTypeLib@CCmdTarget@@UAEJKPAPAUITypeLib@@@Z ; CCmdTarget::GetTypeLib(ulong,ITypeLib * *) .rdata:00431620 dd offset sub_401840 .rdata:00431624 dd offset sub_422A0C .rdata:00431628 dd offset sub_4229BD .rdata:0043162C dd offset sub_422A06 .rdata:00431630 dd offset sub_4229C9 .rdata:00431634 dd offset sub_4229C3 .rdata:00431638 dd offset sub_4229FD 。。。。。。。。。。。。
根据虚函数特点,如果子类重新定义了虚函数后会覆盖父类虚函数,因此未识别出来的均是经过修改的,那么我们只需要对照MFC源码中CWinApp的类布局,就可以知道未识别出的函数是哪些了,具体操作不再赘述,C???App最重要的是InitInstance函数,为虚表第21个函数,我们来看他做了些什么: int __thiscall sub_401880(CWinApp *this) { CWinApp *v1; // esi@1 void *v2; // eax@1 int v3; // eax@2 char v5; // [sp+8h] [bp-2C8h]@1 int v6; // [sp+2CCh] [bp-4h]@1
v1 = this; InitCommonControls(); CWinApp::InitInstance(v1); AfxEnableControlContainer(0); sub_42B8C2("应用程序向导生成的本地应用程序"); sub_40A150(&v5, 0); v6 = 0; *((_DWORD *)v1 + 7) = &v5; CDialog:oModal((CDialog *)&v5); v2 = operator new(1u); LOBYTE(v6) = 1; if ( v2 ) v3 = sub_401000(v2); else v3 = 0; LOBYTE(v6) = 0; j_uninit(v3); v6 = -1; sub_409E20(&v5); return 0; }
我们只来讨论和普通CWinApp构造函数不同的地方: 可以得知v5是我们的C???Dlg,而下面v2 = operator new(1u)显然是某个构造函数,翻译过来就是: BOOL CP2pSearcherApp::InitInstance() { InitCommonControls(); CWinApp::InitInstance(); SetRegistryKey(_T("应用程序向导生成的本地应用程序")); CP2pSearcherDlg dlg; m_pMainWnd=&Dlg; int nResponse=dlg.DoModal(); if (nResponse == IDOK) {
} else if (nResponse == IDCANCEL) {
} dispatch* mydispatch=new dispatch; mydispatch->uninit(); }
下面来看CP2pSearcherDlg: void *__thiscall sub_40A150(void *this, int a2) { void *v2; // esi@1 int v3; // eax@1 int v4; // eax@1 int v5; // edi@1 struct AFX_MODULE_STATE *v6; // eax@1 void *v7; // eax@1 void *v8; // eax@2 void *v9; // eax@4 bool v10; // cf@7 void *v12; // [sp+14h] [bp-30h]@7 void *v13; // [sp+18h] [bp-2Ch]@7 int v14; // [sp+28h] [bp-1Ch]@7 unsigned int v15; // [sp+2Ch] [bp-18h]@7 int v16; // [sp+30h] [bp-14h]@7 int v17; // [sp+40h] [bp-4h]@1
v2 = this; CDialog::CDialog(this, 0x66u, a2); v17 = 0; *(_DWORD *)v2 = &off_431C50; CWnd::CWnd((char *)v2 + 116); *((_DWORD *)v2 + 29) = &off_43326C; CWnd::CWnd((char *)v2 + 196); *((_DWORD *)v2 + 49) = &off_4334A4; CWnd::CWnd((char *)v2 + 276); *((_DWORD *)v2 + 69) = &off_43326C; CWnd::CWnd((char *)v2 + 356); *((_DWORD *)v2 + 89) = &off_43326C; CWnd::CWnd((char *)v2 + 436); *((_DWORD *)v2 + 109) = &off_43311C; CWnd::CWnd((char *)v2 + 516); *((_DWORD *)v2 + 129) = &off_4335F4; *((_DWORD *)v2 + 149) = 0; *((_DWORD *)v2 + 156) = 15; *((_DWORD *)v2 + 155) = 0; *((_BYTE *)v2 + 604) = 0; LOBYTE(v17) = 7; v3 = sub_402BB0((char *)v2 + 628); *((_DWORD *)v2 + 158) = v3; *(_BYTE *)(v3 + 45) = 1; *(_DWORD *)(*((_DWORD *)v2 + 158) + 4) = *((_DWORD *)v2 + 158); **((_DWORD **)v2 + 158) = *((_DWORD *)v2 + 158); *(_DWORD *)(*((_DWORD *)v2 + 158) + 8) = *((_DWORD *)v2 + 158); *((_DWORD *)v2 + 159) = 0; LOBYTE(v17) = 8; v4 = sub_402BF0((char *)v2 + 640); *((_DWORD *)v2 + 161) = v4; *(_BYTE *)(v4 + 57) = 1; *(_DWORD *)(*((_DWORD *)v2 + 161) + 4) = *((_DWORD *)v2 + 161); **((_DWORD **)v2 + 161) = *((_DWORD *)v2 + 161); *(_DWORD *)(*((_DWORD *)v2 + 161) + 8) = *((_DWORD *)v2 + 161); *((_DWORD *)v2 + 162) = 0; v5 = (int)((char *)v2 + 656); *(_DWORD *)(v5 + 4) = 0; *(_DWORD *)(v5 + 8) = 0; *(_DWORD *)(v5 + 12) = 0; LOBYTE(v17) = 10; *((_DWORD *)v2 + 168) = 0; *((_DWORD *)v2 + 169) = 0; *((_DWORD *)v2 + 170) = 0; AfxGetModuleState(); v6 = AfxGetModuleState(); *((_DWORD *)v2 + 28) = LoadIconA(*((HINSTANCE *)v6 + 3), (LPCSTR)0x80); v7 = operator new(1u); LOBYTE(v17) = 11; if ( v7 ) v8 = sub_401000(v7); else v8 = 0; LOBYTE(v17) = 10; *((_DWORD *)v2 + 149) = v8; *((_BYTE *)v2 + 684) = 0; v9 = operator new(0x10u); if ( v9 ) { *(_DWORD *)v9 = 0; *((_DWORD *)v9 + 1) = 0; *((_DWORD *)v9 + 2) = 0; *((_BYTE *)v9 + 12) = 1; } else { v9 = 0; } *((_DWORD *)v2 + 173) = v9; sub_40AB90(v9); *((_DWORD *)v2 + 172) = 0; v15 = 15; v14 = 0; LOBYTE(v13) = 0; LOBYTE(v17) = 12; sub_4016A0(&unk_431DA8, 4); v16 = 60; sub_4085C0(&v12); sub_4016A0(&unk_431B40, 6); v16 = 270; sub_4085C0(&v12); sub_4016A0(&unk_431C3C, 8); v16 = 90; sub_4085C0(&v12); sub_4016A0("hash值", 6); v16 = 280; sub_4085C0(&v12); sub_4016A0(&unk_431C34, 6); v16 = 90; sub_4085C0(&v12); v10 = v15 < 0x10; *((_DWORD *)v2 + 163) = 8; if ( !v10 ) j__free(v13); return v2; } 可以看到虚表为off_431C50: .rdata:00431C50 off_431C50 dd offset loc_42B8BC ; DATA XREF: sub_409E20+21o .rdata:00431C50 ; sub_40A150+41o .rdata:00431C50 ; Exception filter 1 for function 401990 .rdata:00431C54 dd offset sub_40A440 .rdata:00431C58 dd offset nullsub_4 .rdata:00431C5C dd offset unknown_libname_209 ; MFC 3.1-11.0 32bit .rdata:00431C60 dd offset ?OnFinalRelease@CWnd@@UAEXXZ ; CWnd::OnFinalRelease(void) .rdata:00431C64 dd offset sub_4229A6 .rdata:00431C68 dd offset ?_Get_deleter@_Ref_count_base@std@@UBEPAXABVtype_info@@@Z_6 ; std::_Ref_count_base::_Get_deleter(type_info const &) .rdata:00431C6C dd offset sub_4229AC .rdata:00431C70 dd offset sub_4229AC .rdata:00431C74 dd offset ?GetTypeLib@CCmdTarget@@UAEJKPAPAUITypeLib@@@Z ; CCmdTarget::GetTypeLib(ulong,ITypeLib * *) .rdata:00431C78 dd offset sub_401C60 .rdata:00431C7C dd offset sub_422A0C .rdata:00431C80 dd offset sub_4229BD .rdata:00431C84 dd offset sub_422A06 .rdata:00431C88 dd offset sub_423A14 .rdata:00431C8C dd offset sub_4229C3 .rdata:00431C90 dd offset sub_4229FD
同样我们只关注很少的一些,OnInitDialog为初始化函数,GetMessageMap可以得到消息响应函数 OnInitDialog做的最重要的一件事为: if ( !sub_401020(*((_DWORD *)v1 + 149)) ) sub_4243C6("无法连入emule网络", "警告", 0); 而sub_4243C6做的是和上面uninit对应的init,都是dispatch.dll中的
而149对应的变量则在CP2pSearcherDlg构造函数中可以找到踪迹: v7 = operator new(1u); LOBYTE(v17) = 11; if ( v7 ) v8 = sub_401000(v7); else v8 = 0; LOBYTE(v17) = 10; *((_DWORD *)v2 + 149) = v8; *((_BYTE *)v2 + 684) = 0; v9 = operator new(0x10u); if ( v9 ) { *(_DWORD *)v9 = 0; *((_DWORD *)v9 + 1) = 0; *((_DWORD *)v9 + 2) = 0; *((_BYTE *)v9 + 12) = 1; } else { v9 = 0; } *((_DWORD *)v2 + 173) = v9; sub_40AB90(v9); *((_DWORD *)v2 + 172) = 0; v15 = 15; v14 = 0; LOBYTE(v13) = 0; LOBYTE(v17) = 12; sub_4016A0(&unk_431DA8, 4); v16 = 60; sub_4085C0(&v12); sub_4016A0(&unk_431B40, 6); v16 = 270; sub_4085C0(&v12); sub_4016A0(&unk_431C3C, 8); v16 = 90; sub_4085C0(&v12); sub_4016A0("hash值", 6); v16 = 280; sub_4085C0(&v12); sub_4016A0(&unk_431C34, 6); v16 = 90; sub_4085C0(&v12); v10 = v15 < 0x10; *((_DWORD *)v2 + 163) = 8; if ( !v10 ) j__free(v13);
看完了之后我们知道了真正做的是dispatch.dll中的init和uninit,下面我们再来看消息处理: void ****sub_401C60() { return &off_4316D0; } .rdata:004316D0 off_4316D0 dd offset off_432340 ; DATA XREF: sub_401C60o .rdata:004316D4 dd offset dword_4316D8 .rdata:004316D8 dword_4316D8 dd 113h ; DATA XREF: .rdata:004316D4o .rdata:004316DC dd 0 .rdata:004316E0 dd 0 .rdata:004316E4 dd 0 .rdata:004316E8 dd 11h .rdata:004316EC dd offset OnTimer .rdata:004316F0 dd 112h .rdata:004316F4 dd 0 .rdata:004316F8 dd 0 .rdata:004316FC dd 0 .rdata:00431700 dd 1Bh .rdata:00431704 dd offset OnSysCommand 。。。。。。。。。。。
先来看MFC里的相关知识,来说明这里为何这么做: 我们每添加一个消息,都会在消息映射里增加一条,例如 BEGIN_MESSAGE_MAP(CtestmfcDlg, CDialogEx) ON_WM_PAINT() ON_WM_QUERYDRAGICON() ON_BN_CLICKED(IDOK, &CtestmfcDlg::OnBnClickedOk) ON_NOTIFY(NM_RCLICK, IDC_LIST1, &CtestmfcDlg::OnNMRClickList1) END_MESSAGE_MAP() 而这里的第一行和最后一行为宏,对应GetMessageMap函数和结构体 struct AFX_MSGMAP { const AFX_MSGMAP* (PASCAL* pfnGetBaseMap)(); const AFX_MSGMAP_ENTRY* lpEntries; }; struct AFX_MSGMAP_ENTRY { UINT nMessage; // windows message UINT nCode; // control code or WM_NOTIFY code UINT nID; // control ID (or 0 for windows messages) UINT nLastID; // used for entries specifying a range of control id's UINT_PTR nSig; // signature type (action) or pointer to message # AFX_PMSG pfn; // routine to call (or special value) }; 从这里很显然的可以看到如何对应上消息响应了。。。。。。。不用解释了吧
如此,对照前面说的windows消息代码,结合exescope查看控件id,可以吧004316D8开始的AFX_MSGMAP_ENTRY标注成消息回调函数: OnTimer OnSysCommand OnPaint OnDragIcon OnSearch OnSelectSource OnTcnSelChange OnLvnColumnClick OnNMLVRClickList OnNMTCRClickList OnNMLVDoubleClick OnSize
现在你来告诉我,那些函数最重要??
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