东原ARC网站建设公司,合肥seo网站推广外包,天津市建设工程信息交易网,昆明建设厅官方网站珊瑚虫外挂原理分析作者: RunJin runjin000yahoo.com.cn分析工具: softice , OD我的操作系统: win 2000 sp4 , win 98分析对象: QQ2005贺岁版 珊瑚虫外挂为了方便分析,我先把CoralQQ.dll和coralqq.exe先脱壳,这两个文件加的都是超弱壳,脱壳过程不在这里多说. 由于win nt…珊瑚虫外挂原理分析作者: RunJin runjin000yahoo.com.cn分析工具: softice , OD我的操作系统: win 2000 sp4 , win 98分析对象: QQ2005贺岁版 珊瑚虫外挂为了方便分析,我先把CoralQQ.dll和coralqq.exe先脱壳,这两个文件加的都是超弱壳,脱壳过程不在这里多说. 由于win nt 平台和win9x 的差异,珊瑚虫外挂因系统的不同而分开两种工作原理. 我们都知道,珊瑚外挂是给QQ的主程序QQ.exe外挂了一个Coralqq.dll,而完成这个工作的就是coralqq.exe .要加载一个dll文件必须是qq.exe自己的某个线程执行LoadLibraryA,并且以coralqq.dll为参数,但qq.exe本来根本没有这样的一段代码,怎么办?答案很简单,既然它没有,那就让我们帮它加上去,coralqq.exe就是利用WriteProcessMemory帮QQ.exe加上了这样一段代码,并且改变程序流程,让qq.exe先加载coralqq.dll再跳到原来的oep执行. 想了一下,比较合理的方法有:1.在nt内核的系统上,利用远程线程的方法,首先用CreateProcess创建QQ.exe的进程,同时创建了主线程,再用VirtualAllocEx在qq.exe中申请一块内存,然后把我们的代码写进去,最后用CreateRemoteThread在qq的进程中创建另外一个线程,其开始执行的地方正是我们自己加入的代码首地址.2.先用CreateProcess创建QQ进程和主线程,在QQ的内存空间中找个合理的地方写入我们的代码,然后修改某个地方(例如OEP)使QQ先跳去执行我们写入的代码,加载coralqq.dll,修复原来改过的oep,然后跳回oep让程序正常执行.下面就让我们分析一下珊瑚虫的外挂是怎样做到的,首先分析nt平台上的运行过程.用OD载入脱壳后的coralqq.exe,停在下面:00418E2C /$ 55 push ebp00418E2D |. 8BEC mov ebp,esp00418E2F |. 83C4 F0 add esp,-1000418E32 |. B8 648D4100 mov eax,CoralQQ.00418D6400418E37 |. E8 A4BAFEFF call CoralQQ.004048E000418E3C |. A1 F49D4100 mov eax,dword ptr ds:[419DF4]00418E41 |. 33D2 xor edx,edx00418E43 |. E8 30F4FFFF call CoralQQ.0041827800418E48 |. A1 F49D4100 mov eax,dword ptr ds:[419DF4]00418E4D |. 8B00 mov eax,dword ptr ds:[eax]00418E4F |. 83C0 18 add eax,1800418E52 |. E8 F9C6FEFF call CoralQQ.0040555000418E57 |. E8 08A9FEFF call CoralQQ.00403764然后下断点: bp CreateRemoteThread ,然后运行,结果发现,OD根本没有断下,证明珊瑚虫的外挂没有使用远程线程的方法,难道它是用了第二种方法?我们再验证一下:首先在OD中bp CreateProcess,断下,反回后,用winhex打开QQ.exe的内存,把QQ.exe的OEP处改为CC,接着在softice中 bpint 3 ,在OD中按F9运行,接着就是中断在softice中,把oep(464b58)处还原,在再softice下 bpm 464b58 ,然后结束程序,再运行coralqq.exe发现自始至终那个bpm断点还是没有断下,证明珊瑚虫外挂在2000下也没有修改QQ.exe的oep来改变程序流程,晕.没办法,只好在OD中下WriteProcessMemory断点,看看它究竟修改了哪里.00231012 57 push edi00231013 8B4424 24 mov eax,dword ptr ss:[esp24]00231017 A3 70302300 mov dword ptr ds:[233070],eax0023101C 8305 70302300 04 add dword ptr ds:[233070],400231023 E8 5C000000 call jmp.kernel32.CreateProcessA;创建QQ的进程上面创建后的QQ主线程是暂停的,不会马上执行,在win9x下也是这样.第一次中断时堆栈显示:0012EBDC 0040C75C /CALL 到 WriteProcessMemory 来自 CoralQQ.0040C7560012EBE0 00000018 |hProcess 000000180012EBE4 5F000000 |Address 5F0000000012EBE8 00CC0F44 |Buffer 00CC0F440012EBEC 000000D2 |BytesToWrite D2 (210.)0012EBF0 0012EC68 /pBytesWritten 0012EC68第二次:0012EC70 00416231 /CALL 到 WriteProcessMemory 来自 CoralQQ.0041622C0012EC74 00000018 |hProcess 000000180012EC78 5F010000 |Address 5F0100000012EC7C 0012EE9F |Buffer 0012EE9F0012EC80 00000025 |BytesToWrite 25 (37.)0012EC84 0012EFD0 /pBytesWritten 0012EFD0第三次:0012EC70 004162CB /CALL 到 WriteProcessMemory 来自 CoralQQ.004162C60012EC74 00000018 |hProcess 000000180012EC78 77F84BC0 |Address 77F84BC00012EC7C 0012EFC3 |Buffer 0012EFC30012EC80 00000005 |BytesToWrite 50012EC84 0012EFD0 /pBytesWritten 0012EFD0第四次:0012EC70 0041632B /CALL 到 WriteProcessMemory 来自 CoralQQ.004163260012EC74 00000018 |hProcess 000000180012EC78 5F010025 |Address 5F0100250012EC7C 0012EC96 |Buffer 0012EC960012EC80 00000208 |BytesToWrite 208 (520.)0012EC84 0012EFD0 /pBytesWritten 0012EFD0第五次:0012EC70 0041634B /CALL 到 WriteProcessMemory 来自 CoralQQ.004163460012EC74 00000018 |hProcess 000000180012EC78 5F010000 |Address 5F0100000012EC7C 0012EE9F |Buffer 0012EE9F0012EC80 00000025 |BytesToWrite 25 (37.)0012EC84 0012EFD0 /pBytesWritten 0012EFD0留意第三次中断: 77F84BC0 对应着: NtTestAlert 所在库ntdll.dll程序每次执行前都要经过 ntdll.dll 的 NtTestAlert函数,它使函数首句跳到某个地方,从而改变程序流程.00417E7E 8B45 F4 mov eax,dword ptr ss:[ebp-C]00417E81 50 push eax00417E82 E8 DDCDFEFF call jmp.kernel32.ResumeThread;使得QQ的主线程继续执行把 0012efc3 处的E9改为CC,再在softice中bpint 3 ,让其中断后跟踪:001B:77F84BC0 E93BB408E7 JMP 5F010000单步执行跟踪001B:5F010000 B80000015F MOV EAX,5F010000001B:5F010005 B90000005F MOV ECX,5F000000001B:5F01000A FFD1 CALL ECX此时ecx的值为5F000000001B:5F000000 55 PUSH EBP001B:5F000001 8BEC MOV EBP,ESP001B:5F000003 83C4EC ADD ESP,-14001B:5F000006 53 PUSH EBX001B:5F000007 56 PUSH ESI001B:5F000008 8BD8 MOV EBX,EAX001B:5F00000A 896DFC MOV [EBP-04],EBP001B:5F00000D 8B431C MOV EAX,[EBX1C]001B:5F000010 8B55FC MOV EDX,[EBP-04]001B:5F000013 83C204 ADD EDX,04001B:5F000016 8902 MOV [EDX],EAX001B:5F000018 8B431C MOV EAX,[EBX1C]001B:5F00001B 8945EC MOV [EBP-14],EAX001B:5F00001E C745FC05000000 MOV DWORD PTR [EBP-04],00000005001B:5F000025 8D45F8 LEA EAX,[EBP-08]001B:5F000028 50 PUSH EAX001B:5F000029 6A40 PUSH 40001B:5F00002B 8D45FC LEA EAX,[EBP-04]001B:5F00002E 50 PUSH EAX001B:5F00002F 8D45EC LEA EAX,[EBP-14]001B:5F000032 50 PUSH EAX001B:5F000033 6AFF PUSH FF001B:5F000035 FF15C600005F CALL [5F0000C6]001B:5F00003B 8B431C MOV EAX,[EBX1C]001B:5F00003E 8B5320 MOV EDX,[EBX20]001B:5F000041 8910 MOV [EAX],EDX ;恢复Ntdll.NtTestAlert入口处001B:5F000043 8A5324 MOV DL,[EBX24]001B:5F000046 885004 MOV [EAX04],DL001B:5F000049 C745FC05000000 MOV DWORD PTR [EBP-04],00000005001B:5F000050 8D45F8 LEA EAX,[EBP-08]001B:5F000053 50 PUSH EAX001B:5F000054 8B45F8 MOV EAX,[EBP-08]001B:5F000057 50 PUSH EAX001B:5F000058 8D45FC LEA EAX,[EBP-04]001B:5F00005B 50 PUSH EAX001B:5F00005C 8D45EC LEA EAX,[EBP-14]001B:5F00005F 50 PUSH EAX001B:5F000060 6AFF PUSH FF001B:5F000062 FF15CA00005F CALL [5F0000CA]001B:5F000068 8B7318 MOV ESI,[EBX18]001B:5F00006B 4E DEC ESI001B:5F00006C 85F6 TEST ESI,ESI001B:5F00006E 7C4C JL 5F0000BC001B:5F000070 46 INC ESI001B:5F000071 8D4325 LEA EAX,[EBX25]001B:5F000074 8BD8 MOV EBX,EAX001B:5F000076 33D2 XOR EDX,EDX001B:5F000078 8BC3 MOV EAX,EBX001B:5F00007A 66833800 CMP WORD PTR [EAX],00001B:5F00007E 740C JZ 5F00008C001B:5F000080 42 INC EDX001B:5F000081 83C002 ADD EAX,02001B:5F000084 81FA03010000 CMP EDX,00000103001B:5F00008A 75EE JNZ 5F00007A001B:5F00008C 8BC2 MOV EAX,EDX001B:5F00008E 03C0 ADD EAX,EAX001B:5F000090 668945F0 MOV [EBP-10],AX001B:5F000094 6683C002 ADD AX,02001B:5F000098 668945F2 MOV [EBP-0E],AX001B:5F00009C 8BC3 MOV EAX,EBX001B:5F00009E 8945F4 MOV [EBP-0C],EAX001B:5F0000A1 8D45FC LEA EAX,[EBP-04]001B:5F0000A4 50 PUSH EAX001B:5F0000A5 8D45F0 LEA EAX,[EBP-10]001B:5F0000A8 50 PUSH EAX001B:5F0000A9 6A00 PUSH 00001B:5F0000AB 6A00 PUSH 00001B:5F0000AD FF15CE00005F CALL [5F0000CE] ;call LoadLibraryA001B:5F0000B3 81C308020000 ADD EBX,00000208001B:5F0000B9 4E DEC ESI001B:5F0000BA 75BA JNZ 5F000076001B:5F0000BC 5E POP ESI001B:5F0000BD 5B POP EBX001B:5F0000BE 8BE5 MOV ESP,EBP001B:5F0000C0 5D POP EBP001B:5F0000C1 C3 RET001B:5F0000C2 0000 ADD [EAX],AL001B:5F0000C4 0000 ADD [EAX],AL001B:5F0000C6 C4BFF877C4BF LES EDI,[EDIBFC477F8]001B:5F0000CC F8 CLC001B:5F0000CD 7761 JA 5F000130001B:5F0000CF 32F8 XOR BH,AL001B:5F0000D1 7700 JA 5F0000D3我们再分析一下win9x下珊瑚虫的外挂又是怎样运行的.再次用OD载入Coralqq.exe00415C9D mov dword ptr ss:[ebp-C],ecx00415CA0 mov dword ptr ss:[ebp-4],edx00415CA3 mov dword ptr ss:[ebp-8],eax00415CA6 xor ebx,ebx00415CA8 call jmp.kernel32.GetVersion ;判断操作系统00415CAD test eax,8000000000415CB2 je short CORALQQ.00415CFE00415CB4 xor edi,edi00415CB6 xor esi,esi00415CB8 jmp short CORALQQ.00415CE700415CBA /cmp esi,dword ptr ss:[ebp-24]00415CBD |je short CORALQQ.00415CE200415CBF |mov eax,dword ptr ss:[ebp-4]00415CC2 |mov edx,dword ptr ss:[ebp-24]00415CC5 |mov dword ptr ds:[eax],edx00415CC7 |cmp dword ptr ss:[ebp-18],100000415CCE |jnz short CORALQQ.00415CDF00415CD0 |push ebp ; /Arg100415CD1 |call CORALQQ.00415BD4 ; /CoralQQ.00415BD400415CD6 |pop ecx00415CD7 |test al,al00415CD9 |je short CORALQQ.00415CDF00415CDB |mov bl,100415CDD |jmp short CORALQQ.00415D2900415CDF |mov esi,dword ptr ss:[ebp-24]00415CE2 |mov eax,dword ptr ss:[ebp-1C]00415CE5 |add edi,eax00415CE7 push 1C ; /BufSize 1C (28.)00415CE9 |lea eax,dword ptr ss:[ebp-28] ; |00415CEC |push eax ; |Buffer00415CED |push edi ; |Address00415CEE |mov eax,dword ptr ss:[ebp-8] ; |00415CF1 |push eax ; |hProcess00415CF2 |call jmp.kernel32.VirtualQueryEx ; /VirtualQueryEx 获得内存业面信息00415CF7 |cmp eax,1C00415CFA /je short CORALQQ.00415CBA00415CFC jmp short CORALQQ.00415D29上面的代码是判断操作系统的版本,如果是win9x的话就先跳到415ce7,00415A4B | /8lea eax,dword ptr ss:[ebp-8]00415A4E |. 5push eax ; /pBytesWritten00415A4F |. 5push edi ; |BytesToWrite00415A50 |. 8mov eax,dword ptr ss:[ebp-4] ; |00415A53 |. 5push eax ; |Buffer00415A54 |. 5push esi ; |Address00415A55 |. 5push ebx ; |hProcess00415A56 |. Ecall jmp.kernel32.WriteProcessMemory ; /WriteProcessMemory看一下此时的堆栈:0067EA5C 0000000C |hProcess 0000000C0067EA60 83138AAC |Address 83138AAC0067EA64 0067EABC |Buffer 0067EABC0067EA68 00000292 |BytesToWrite 292 (658.)0067EA6C 0067EA7C /pBytesWritten 0067EA7C它把缓冲区 0067eabc的658的字节写进QQ.exe的内存 83138aac处,在win98下,进程内存中的共享(MMF)分区是0x80000000~0xbfffffff,所有的内存映射文件和系统共享DLL将加载在这个地址,而那些映射文件和系统共享DLL往往都在比较高的地址,所以说,从80000000地址对上的一大段地址空间往往是比较空闲的,当然,并不是说这些地址就可以乱读乱写,至于这个83138aac的地址值具体是怎样计算出来的,我还没有分析清楚,但我想到另外一种可行的方法,而且经过我自己编程证实,那就是以1000h大小为单位,从80000000开始用WriteProcessMemory一直往上写数据,直到写入成功,证明那段1000h的地址可用,而且1000h大小的内存空间已经够我们放代码的了,之所以用1000h为单位大小,是因为考虑到块对齐.继续跟踪:00415A39 |. 8D45 F8 lea eax,dword ptr ss:[ebp-8]00415A3C |. 50 push eax ; /pOldProtect00415A3D |. 6A 40 push 40 ; |NewProtect PAGE_EXECUTE_READWRITE00415A3F |. 57 push edi ; |Size00415A40 |. 56 push esi ; |Address00415A41 |. 53 push ebx ; |hProcess00415A42 |. E8 85F2FEFF call jmp.kernel32.VirtualProtectEx ; /VirtualProtectEx上面的代码是改变QQ.exe的oep处的属性,使其可读可写可执行,为改写oep处的代码做准备接着,又一次中断在WriteProcessMemory看看堆栈:0067EA5C 0000000C |hProcess 0000000C0067EA60 00464B58 |Address 464B580067EA64 0067EE46 |Buffer 0067EE460067EA68 00000005 |BytesToWrite 50067EA6C 0067EA7C /pBytesWritten 0067EA7C464b58就是QQ.exe的OEP,很明显,它要改变oep来改变程序流程!! 好了,我们又用那套方法,把0067eea6的第一个字节改为cc,在softice中bpint 3,然后中断,再跟踪. 在softice下中断后:0167:00464B58 E91328CE82 JMP 83147370 0167:83147370 C705584B4600558BEC6AMOV DWORD PTR [00464B58],6AEC8B55 ;马上恢复oep处的代码0167:8314737A C6055C4B4600FF MOV BYTE PTR [00464B5C],FF0167:83147381 68FA731483 PUSH 831473FA0167:83147386 6838000000 PUSH 000000380167:8314738B 6A40 PUSH 400167:8314738D FF15F6731483 CALL [KERNEL32!GlobalAlloc] ;再申请内存0167:83147393 C700B85077F7 MOV DWORD PTR [EAX],F77750B8 ;从这里开始一直填入新数据0167:83147399 C74004BFFFD068 MOV DWORD PTR [EAX04],68D0FFBF0167:831473A0 C7400870731483 MOV DWORD PTR [EAX08],831473700167:831473A7 C7400CB89348E9 MOV DWORD PTR [EAX0C],E94893B80167:831473AE C74010BFFFD0B8 MOV DWORD PTR [EAX10],B8D0FFBF0167:831473B5 C74014584B4600 MOV DWORD PTR [EAX14],00464B580167:831473BC C74018FFE0C705 MOV DWORD PTR [EAX18],05C7E0FF0167:831473C3 C7401C584B4600 MOV DWORD PTR [EAX1C],00464B580167:831473CA C74020558BEC6A MOV DWORD PTR [EAX20],6AEC8B550167:831473D1 C74024C6055C4B MOV DWORD PTR [EAX24],4B5C05C60167:831473D8 C740284600FF68 MOV DWORD PTR [EAX28],68FF00460167:831473DF C7402CFA731483 MOV DWORD PTR [EAX2C],831473FA0167:831473E6 C7403068380000 MOV DWORD PTR [EAX30],000038680167:831473ED C74034006A40FF MOV DWORD PTR [EAX34],FF406A000167:831473F4 FFE0 JMP EAX ;此时eax为 0063059C0167:0063059C B85077F7BF MOV EAX,KERNEL32!LoadLibraryA;加载Coralqq.dll0167:006305A1 FFD0 CALL EAX0167:006305A3 6870731483 PUSH 831473700167:006305A8 B89348E9BF MOV EAX,COMCTL32!ORD_00490167:006305AD FFD0 CALL EAX0167:006305AF B8584B4600 MOV EAX,00464B58 0167:006305B4 FFE0 JMP EAX ;跳回QQ.exe的入口点分析完毕.到了这里,我们可以总结一下了,在win2000/xp下coralqq.exe先创建QQ的进程,同时也就创建了QQ的暂停的主线程,接着往QQ进程的内存写入代码,修改Ntdll.NtTestAlert的代码跳让程序跳到自己的代码处执行,在执行的过程中恢复Ntdll.NtTestAlert处被改了的代码,同时加载Coralqq.dll.在win9x下,coralqq.exe先创建QQ的进程,同时也就创建了QQ的暂停的主线程,接着往QQ.exe的内存写数据,改写QQ.exe的oep从而达到改变程序流程的目的,让其先执行加入了的代码,加载Coralqq.dll,加载完后再跳到原来的QQ.exe的oep继续执行.其实在win2000/xp下面完全可以用远程线程的方法来实现加载dll文件,我后来自己编程实现了外挂这一步. 也许有读者读完这编文章后会问:加载了coralqq.dll又有什么用?它是怎样显IP的?其实,要显IP当然要修改QQ的内存中的代码,而修改内存代码这一步是在加载coralqq.dll的时候由coralqq.dll完成的.也就是说,在执行LoadLibrary的过程中系统会执行corall.dll的 LibMain ,修改的过程就在LibMain中完成了!而说到显IP的原理,抱歉,不在我们这编文章的讨论范围之内,我们只是讨论外挂中挂这一步.下面是我写的代码,可以做出一个顶替Coralqq.exe的程序,但原理上和Coralqq.exe有一点点不同.586.model flat, stdcalloption casemap :none ; case sensitiveinclude windows.incinclude kernel32.incincludelib kernel32.lib.dataqq db ./QQ.exe,0ikeyname db qq,0isecname db main,0szBuffer dw 50 dup(0)dllname db ./CoralQQ.dll,0szkernel32 db Kernel32.dll,0dllin dd 0szloadlibrary db LoadLibraryA,0oaddr dd 0wriaddr dd 0ininame db ./CoralQQ.ini,0.data?align dwordcon CONTEXT align dwordcon2 CONTEXT stStartUp STARTUPINFO ?stProcInfo PROCESS_INFORMATION ?.code start: main proc local wrisize:dword ;用来存放要写入的代码的大小 local num:dword local oldpro:dword local lastwri:dword local wribase:dword ;用来存放写入代码的基址 invoke GetPrivateProfileString,offset isecname,offset ikeyname,/ offset szloadlibrary,offset szBuffer,/ sizeof szBuffer,offset ininame ;从Coralqq.ini中获取QQ程序的路径 invoke GetModuleHandle,offset szkernel32 invoke GetProcAddress,eax,offset szloadlibrary mov dllin,eax invoke GetStartupInfo,addr stStartUp invoke CreateProcess,NULL,offset szBuffer,NULL,NULL,FALSE,/ CREATE_SUSPENDED,NULL,NULL,addr stStartUp,addr stProcInfo ;创建QQ进程 cmp eax,0 jz exit invoke GetVersion test eax,080000000h ;判断操作系统类型 jnz win9x invoke VirtualAllocEx,stProcInfo.hProcess,NULL,01000h,MEM_COMMIT,/ PAGE_EXECUTE_READWRITE ;在QQ内存中分配空间 mov oaddr,eax invoke WriteProcessMemory,stProcInfo.hProcess,oaddr,offset dllname,/ sizeof dllname,addr num ;写入数据 invoke CreateRemoteThread,stProcInfo.hProcess,NULL,0,dllin,oaddr,0,/ addr num ;创建远程线程 invoke CloseHandle,eax invoke ResumeThread,stProcInfo.hThread ;让QQ继续运行 invoke ExitProcess,0 retwin9x: mov wribase,oepwrite mov wrisize,codeend-oepwrite invoke VirtualProtect,wribase,wrisize,/ PAGE_EXECUTE_READWRITE,addr oldpro ;改变这个程序的要写入代码的地方的属性,其实可以在编译时加上开关 mov wrisize,codeend-codewrite mov wriaddr,080000000h sub wriaddr,1000hagain: add wriaddr,1000h mov wribase,codewrite invoke WriteProcessMemory,stProcInfo.hProcess,wriaddr,/ wribase,wrisize,addr num ;写入代码 mov eax,wrisize cmp eax,num jnz again mov eax,wriaddr mov ebx,chan0-4 mov [ebx],eax invoke VirtualProtectEx,stProcInfo.hProcess,0464b58h,7,/ PAGE_EXECUTE_READWRITE,addr oldpro ;改变QQ.exe的oep处的属性 mov wribase,oepwrite invoke WriteProcessMemory,stProcInfo.hProcess,0464b58h, wribase,7,/ addr num ;写入数据 mov eax,dllin mov ebx,chan2-4 mov [ebx],eax mov eax,codeend-codewrite add eax,wriaddr mov ebx,chan1-4 mov [ebx],eax mov wribase,codewrite mov wrisize,codeend-codewrite invoke WriteProcessMemory,stProcInfo.hProcess,wriaddr,/ wribase,wrisize,addr num mov eax,codeend-codewrite add eax,wriaddr mov lastwri,eax invoke WriteProcessMemory,stProcInfo.hProcess,lastwri,offset dllname,/ sizeof dllname,addr num invoke ResumeThread,stProcInfo.hThread ;让QQ继续执行 exit: invoke ExitProcess,0 ret main endp;下面的都是要写入到QQ.exe的内存的附加代码,但有些数值在写入前要实时修正oepwrite: mov eax,0chan0: jmp eaxcodewrite: mov eax,0464b58hpush 6aec8b55hpop [eax]mov eax,0464b5chpush 101868ffhpop [eax]push 080000000chan1: push 464b58hmov eax,0chan2: jmp eaxcodeend:end start
