-
-
[原创]实现一个压缩壳，并给它加点“料”
-
发表于: 2022-8-12 21:20
-
学完科锐第三阶段壳的课程内容之后，我发现，实现压缩壳，必须对PE格式十分熟悉，其次，解压缩代码需要编写shellcode，也是十分麻烦的环节。有了两者的结合，我们才能写好一个真正的压缩壳。
首先上一张图，让大家直观地感受到一个壳程序是如何运行起来的。
左边是壳PE，壳程序有一个PE头，节表1是空节，用来存放解压缩后的原程序PE，节表2此时存储的是压缩后的原PE。节表3则是壳代码节，壳PE运行起来后，首先就是进入入口点，运行节表3的代码，解压缩节表2，然后将结果覆盖PE头＋节表1的位置，修复完导入表、重定位表，jmp到原程序的入口点处即可。
原理不变，我这里加了点“料”，新增了节4和节5，存储了相关的信息，让压缩壳的脱壳过程变难，往后看就知道了。
1.为了生成一个新的壳PE，我们一步步来，首先是PE头，俗话说靠山吃山，靠水吃水，这个PE头我就直接拿原程序的PE头来代替了，只不过需要改一些数据：
2.新PE头里一些需要修改的数据，比如SizeOfImage，我们目前还没有，需要等我们构造出节表1、2、3、4、5之后，才知道。接下来，先构造节表1的表头，节表1是个空节，它的大小只要够存放原程序的节表即可，多给一点也没关系，我这里直接给了SizeOfImage。（由于是空节，所以这里并不需要考虑节表1的数据内容）
3.接着是节表2，这个节要存放原PE的压缩数据，先设计表头（使用了PointerToRelocations和PointerToLinenumbers这两个没啥用的字段，存放压缩大小信息，留着给后面shellcode用）
然后将PE压缩，压缩前我把节表、导入表、重定位表保存并清空，到时候由shellcode进行还原。
4.接着是节表3，该节表存放的是解压缩PE、还原导入表、重定位表，运行原程序的至关重要的shellcode，先设计表头
至于节表3的数据内容，也就是shellcode，等我把节表、PE设计完，我再说
5.接着是节表4，节表4是我额外增加的一个，用来存储步骤3中保存的原节表表头、原导入表、原重定位表，首先设计节表4表头
然后把刚才保存的原节表表头、原导入表、原重定位表信息，按顺序写入到缓冲区里。
6.还剩最后一个节表5，是一个空节，壳代码还原原PE时，要还原导入表，于是这个节的作用就体现出来了，shellcode在这里玩了一波偷梁换柱，直接毙掉了x64dbg的脱壳后导入表自动修复功能，等会介绍shellcode的时候你们就知道了。设计节表5的表头
至此，新的壳PE结构我们就设计好了，然后将新PE头、节表234写入到新文件（节表1、5是空节，不用写入），就大功告成，加壳完毕！
由于壳PE可能是随机基址，所以执行shellcode时，一定要确保它的代码跟地址无关。我的shellcode是在VS上编译的，为了保证VS不会生成多余的代码，要修改以下几个设置：
然后就是最麻烦的shellcode代码编写了。首先要清楚shellcode代码的功能：
1.要解压缩，那么必定要调用库的API，如果直接调用的话，call的就是死地址，违背了地址无关原则。那么使用LoadLibrary然后GetProcAddress？显然也不行，LoadLibrary和GetProcAddress也是死地址，所以我们要自己实现LoadLibrary和GetProcAddress的功能。
首先通过_PEB来拿到kernel32的模块基址
然后通过kernel32的导出函数表，拿到GetProcAddress函数地址，代码如下：
有了GetProcAddress函数地址和kernel32的基址，同理就能拿到LoadLibrary函数地址了（注意定义字符串变量时，用单个字符一个一个排列，在汇编里面看就是db出来的，否则字符串会有一个常量区地址，影响shellcode的通用性）
2.有了LoadLibrary和GetProcAddress，就可以使用任何库函数了，解压缩便是小菜一碟。
3.解压缩完毕，得到了原PE，接下来就是将原PE覆盖到现在的PE头+节表1的地方，同时还原节表头、导入表和重定位表，相当于LoadPE的功能了
这里重点要介绍的，就是还原导入表的过程，也是整篇文章的核心主题，加点“料”。我在遍历还原导入表时，并没有直接将API的地址填入到IAT里，而是将节表5的地址，从起始位置开始，每隔16个字节，将地址填入到IAT里，然后在对应的节表5地址上填入push 真实函数地址 + retn的汇编指令。这样一来，原PE程序运行调用API时，就会跳到节表5里面，再从节表5里面跳到真实API地址，直接干掉了x64dbg的脱壳导入表自动修复功能。嘿嘿~~
最后来看看效果，对扫雷进行加壳，加壳后的程序可以正常运行
先用x64找到真实入口点，进行一波dump操作
dump后无法直接运行
然后去x64里使用自动搜索修复导入表的功能，可以看到，IAT这里存放的压根就不是真实API的地址，所以x64也无法识别出来。
搞定，收工！
NumberOfSections --节表数量，要改为5
AddressOfEntryPoint --入口点，要改为节表3里的代码入口
SizeOfImage --PE在内存中的大小，要改为新的PE的内存大小
pSecHdr --节表头，要拓展为5个节表
void CPacker::GetNewPeHdr(){ //拷贝原PE的PE头
m_dwNewPeHdrSize = m_pNtHdr->OptionalHeader.SizeOfHeaders;
m_pNewPeHdr = new BYTE[m_dwNewPeHdrSize];
CopyMemory(m_pNewPeHdr, m_pDosHdr, m_dwNewPeHdrSize);
//修改
auto pDosHdr = (PIMAGE_DOS_HEADER)m_pNewPeHdr;
auto pNtHdr = (PIMAGE_NT_HEADERS)(m_pNewPeHdr + pDosHdr->e_lfanew);
auto pSecHdr = (PIMAGE_SECTION_HEADER)
((LPBYTE)&pNtHdr->OptionalHeader + pNtHdr->FileHeader.SizeOfOptionalHeader);
pNtHdr->FileHeader.NumberOfSections = 5;
pNtHdr->OptionalHeader.AddressOfEntryPoint = m_newSecHdr[2].VirtualAddress;
pNtHdr->OptionalHeader.SizeOfImage = m_newSecHdr[4].VirtualAddress + m_newSecHdr[4].Misc.VirtualSize;
//清空DataDirectory目录
ZeroMemory(pNtHdr->OptionalHeader.DataDirectory, sizeof(pNtHdr->OptionalHeader.DataDirectory));
//修改新的节表头
CopyMemory(pSecHdr, m_newSecHdr, sizeof(m_newSecHdr));
}NumberOfSections --节表数量，要改为5
AddressOfEntryPoint --入口点，要改为节表3里的代码入口
SizeOfImage --PE在内存中的大小，要改为新的PE的内存大小
pSecHdr --节表头，要拓展为5个节表
void CPacker::GetNewPeHdr(){ //拷贝原PE的PE头
m_dwNewPeHdrSize = m_pNtHdr->OptionalHeader.SizeOfHeaders;
m_pNewPeHdr = new BYTE[m_dwNewPeHdrSize];
CopyMemory(m_pNewPeHdr, m_pDosHdr, m_dwNewPeHdrSize);
//修改
auto pDosHdr = (PIMAGE_DOS_HEADER)m_pNewPeHdr;
auto pNtHdr = (PIMAGE_NT_HEADERS)(m_pNewPeHdr + pDosHdr->e_lfanew);
auto pSecHdr = (PIMAGE_SECTION_HEADER)
((LPBYTE)&pNtHdr->OptionalHeader + pNtHdr->FileHeader.SizeOfOptionalHeader);
pNtHdr->FileHeader.NumberOfSections = 5;
pNtHdr->OptionalHeader.AddressOfEntryPoint = m_newSecHdr[2].VirtualAddress;
pNtHdr->OptionalHeader.SizeOfImage = m_newSecHdr[4].VirtualAddress + m_newSecHdr[4].Misc.VirtualSize;
//清空DataDirectory目录
ZeroMemory(pNtHdr->OptionalHeader.DataDirectory, sizeof(pNtHdr->OptionalHeader.DataDirectory));
//修改新的节表头
CopyMemory(pSecHdr, m_newSecHdr, sizeof(m_newSecHdr));
}//空节
strcpy((char*)m_newSecHdr[0].Name, ".cr42");
m_newSecHdr[0].Misc.VirtualSize = m_pNtHdr->OptionalHeader.SizeOfImage;
m_newSecHdr[0].VirtualAddress = m_pSecHdr[0].VirtualAddress;
m_newSecHdr[0].SizeOfRawData = 0;
m_newSecHdr[0].PointerToRawData = 0;
m_newSecHdr[0].Characteristics =
IMAGE_SCN_MEM_EXECUTE | IMAGE_SCN_MEM_WRITE | IMAGE_SCN_MEM_READ;
//空节
strcpy((char*)m_newSecHdr[0].Name, ".cr42");
m_newSecHdr[0].Misc.VirtualSize = m_pNtHdr->OptionalHeader.SizeOfImage;
m_newSecHdr[0].VirtualAddress = m_pSecHdr[0].VirtualAddress;
m_newSecHdr[0].SizeOfRawData = 0;
m_newSecHdr[0].PointerToRawData = 0;
m_newSecHdr[0].Characteristics =
IMAGE_SCN_MEM_EXECUTE | IMAGE_SCN_MEM_WRITE | IMAGE_SCN_MEM_READ;
//压缩数据节
strcpy((char*)m_newSecHdr[1].Name, ".data");
m_newSecHdr[1].Misc.VirtualSize = GetAlign(m_dwComSecSize, m_pNtHdr->OptionalHeader.SectionAlignment);
m_newSecHdr[1].VirtualAddress = m_newSecHdr[0].VirtualAddress + m_newSecHdr[0].Misc.VirtualSize;
m_newSecHdr[1].SizeOfRawData = m_dwComSecSize;
m_newSecHdr[1].PointerToRawData = m_pNtHdr->OptionalHeader.SizeOfHeaders;
m_newSecHdr[1].Characteristics = IMAGE_SCN_MEM_READ;
m_newSecHdr[1].PointerToRelocations = m_dwComSize; //压缩后大小
m_newSecHdr[1].PointerToLinenumbers = m_dwSrcPeSize;//压缩前大小
//压缩数据节
strcpy((char*)m_newSecHdr[1].Name, ".data");
m_newSecHdr[1].Misc.VirtualSize = GetAlign(m_dwComSecSize, m_pNtHdr->OptionalHeader.SectionAlignment);
m_newSecHdr[1].VirtualAddress = m_newSecHdr[0].VirtualAddress + m_newSecHdr[0].Misc.VirtualSize;
m_newSecHdr[1].SizeOfRawData = m_dwComSecSize;
m_newSecHdr[1].PointerToRawData = m_pNtHdr->OptionalHeader.SizeOfHeaders;
m_newSecHdr[1].Characteristics = IMAGE_SCN_MEM_READ;
m_newSecHdr[1].PointerToRelocations = m_dwComSize; //压缩后大小
m_newSecHdr[1].PointerToLinenumbers = m_dwSrcPeSize;//压缩前大小
bool CPacker::GetCompressData()
{ COMPRESSOR_HANDLE hCompressor = NULL;
BOOL Success = CreateCompressor(
COMPRESS_ALGORITHM_XPRESS_HUFF,
NULL,
&hCompressor
);
m_pComData = new BYTE[m_dwSrcPeSize + 0x28];
LPBYTE m_pSrcPeTmp = new BYTE[m_dwSrcPeSize];
CopyMemory(m_pSrcPeTmp, m_pSrcPe, m_dwSrcPeSize);
PIMAGE_DOS_HEADER m_pDosHdrTmp = (PIMAGE_DOS_HEADER)m_pSrcPeTmp;
PIMAGE_NT_HEADERS m_pNtHdrTmp = (PIMAGE_NT_HEADERS)(m_pSrcPeTmp + m_pDosHdrTmp->e_lfanew);
PIMAGE_SECTION_HEADER m_pSecHdrTmp = (PIMAGE_SECTION_HEADER)
((LPBYTE)&m_pNtHdrTmp->OptionalHeader + m_pNtHdrTmp->FileHeader.SizeOfOptionalHeader);
//1.在压缩前，把节表保存并清空
nSecNum = m_pNtHdrTmp->FileHeader.NumberOfSections;
CopyMemory(m_pSaveSecHdr, m_pSecHdrTmp, nSecNum * 40);
ZeroMemory(m_pSecHdrTmp, nSecNum * 40);
//2.把导入表保存并清空
m_pImportAddr = m_pNtHdrTmp->OptionalHeader.DataDirectory[1].VirtualAddress;
nImpSize = m_pNtHdrTmp->OptionalHeader.DataDirectory[1].Size;
ZeroMemory(&(m_pNtHdrTmp->OptionalHeader.DataDirectory[1]), 8);
//3.把重定位表保存并清空
m_pRelocAddr = m_pNtHdrTmp->OptionalHeader.DataDirectory[5].VirtualAddress;
nRelocSize = m_pNtHdrTmp->OptionalHeader.DataDirectory[5].Size;
ZeroMemory(&(m_pNtHdrTmp->OptionalHeader.DataDirectory[5]), 8);
Success = Compress(
hCompressor,
m_pSrcPeTmp,
m_dwSrcPeSize,
m_pComData,
m_dwSrcPeSize + 0x28,
&m_dwComSize
);
return true;
}bool CPacker::GetCompressData()
{ COMPRESSOR_HANDLE hCompressor = NULL;
BOOL Success = CreateCompressor(
COMPRESS_ALGORITHM_XPRESS_HUFF,
NULL,
&hCompressor
);
m_pComData = new BYTE[m_dwSrcPeSize + 0x28];
LPBYTE m_pSrcPeTmp = new BYTE[m_dwSrcPeSize];
CopyMemory(m_pSrcPeTmp, m_pSrcPe, m_dwSrcPeSize);
PIMAGE_DOS_HEADER m_pDosHdrTmp = (PIMAGE_DOS_HEADER)m_pSrcPeTmp;
PIMAGE_NT_HEADERS m_pNtHdrTmp = (PIMAGE_NT_HEADERS)(m_pSrcPeTmp + m_pDosHdrTmp->e_lfanew);
PIMAGE_SECTION_HEADER m_pSecHdrTmp = (PIMAGE_SECTION_HEADER)
((LPBYTE)&m_pNtHdrTmp->OptionalHeader + m_pNtHdrTmp->FileHeader.SizeOfOptionalHeader);
//1.在压缩前，把节表保存并清空
nSecNum = m_pNtHdrTmp->FileHeader.NumberOfSections;
CopyMemory(m_pSaveSecHdr, m_pSecHdrTmp, nSecNum * 40);
ZeroMemory(m_pSecHdrTmp, nSecNum * 40);
//2.把导入表保存并清空
m_pImportAddr = m_pNtHdrTmp->OptionalHeader.DataDirectory[1].VirtualAddress;
nImpSize = m_pNtHdrTmp->OptionalHeader.DataDirectory[1].Size;
ZeroMemory(&(m_pNtHdrTmp->OptionalHeader.DataDirectory[1]), 8);
//3.把重定位表保存并清空
m_pRelocAddr = m_pNtHdrTmp->OptionalHeader.DataDirectory[5].VirtualAddress;
nRelocSize = m_pNtHdrTmp->OptionalHeader.DataDirectory[5].Size;
ZeroMemory(&(m_pNtHdrTmp->OptionalHeader.DataDirectory[5]), 8);
Success = Compress(
hCompressor,
m_pSrcPeTmp,
m_dwSrcPeSize,
m_pComData,
m_dwSrcPeSize + 0x28,
&m_dwComSize
);
return true;
}//代码节
strcpy((char*)m_newSecHdr[2].Name, ".text");
m_newSecHdr[2].Misc.VirtualSize = GetAlign(m_dwCodeSecSize, m_pNtHdr->OptionalHeader.SectionAlignment);
m_newSecHdr[2].VirtualAddress = m_newSecHdr[1].VirtualAddress + m_newSecHdr[1].Misc.VirtualSize;
m_newSecHdr[2].SizeOfRawData = m_dwCodeSecSize;
m_newSecHdr[2].PointerToRawData = m_newSecHdr[1].PointerToRawData + m_newSecHdr[1].SizeOfRawData;
m_newSecHdr[2].Characteristics = IMAGE_SCN_MEM_EXECUTE | IMAGE_SCN_MEM_WRITE | IMAGE_SCN_MEM_READ;
//代码节
strcpy((char*)m_newSecHdr[2].Name, ".text");
m_newSecHdr[2].Misc.VirtualSize = GetAlign(m_dwCodeSecSize, m_pNtHdr->OptionalHeader.SectionAlignment);
m_newSecHdr[2].VirtualAddress = m_newSecHdr[1].VirtualAddress + m_newSecHdr[1].Misc.VirtualSize;
m_newSecHdr[2].SizeOfRawData = m_dwCodeSecSize;
m_newSecHdr[2].PointerToRawData = m_newSecHdr[1].PointerToRawData + m_newSecHdr[1].SizeOfRawData;
m_newSecHdr[2].Characteristics = IMAGE_SCN_MEM_EXECUTE | IMAGE_SCN_MEM_WRITE | IMAGE_SCN_MEM_READ;
//存放原节表、导入表、重定位表的节
strcpy((char*)m_newSecHdr[3].Name, ".info");
m_newSecHdr[3].Misc.VirtualSize = GetAlign(m_dwTableSecSize, m_pNtHdr->OptionalHeader.SectionAlignment);
m_newSecHdr[3].VirtualAddress = m_newSecHdr[2].VirtualAddress + m_newSecHdr[2].Misc.VirtualSize;
m_newSecHdr[3].SizeOfRawData = m_dwTableSecSize;
m_newSecHdr[3].PointerToRawData = m_newSecHdr[2].PointerToRawData + m_newSecHdr[2].SizeOfRawData;
m_newSecHdr[3].Characteristics = IMAGE_SCN_MEM_EXECUTE | IMAGE_SCN_MEM_WRITE | IMAGE_SCN_MEM_READ;
//存放原节表、导入表、重定位表的节
strcpy((char*)m_newSecHdr[3].Name, ".info");
m_newSecHdr[3].Misc.VirtualSize = GetAlign(m_dwTableSecSize, m_pNtHdr->OptionalHeader.SectionAlignment);
m_newSecHdr[3].VirtualAddress = m_newSecHdr[2].VirtualAddress + m_newSecHdr[2].Misc.VirtualSize;
m_newSecHdr[3].SizeOfRawData = m_dwTableSecSize;
m_newSecHdr[3].PointerToRawData = m_newSecHdr[2].PointerToRawData + m_newSecHdr[2].SizeOfRawData;
m_newSecHdr[3].Characteristics = IMAGE_SCN_MEM_EXECUTE | IMAGE_SCN_MEM_WRITE | IMAGE_SCN_MEM_READ;
bool CPacker::GetTable()
{ m_dwTableSize = nSecNum * 40 + 4 + 8 + 8;
m_pTable = new BYTE[m_dwTableSize];
RtlCopyMemory(m_pTable, &nSecNum, 4);
RtlCopyMemory(m_pTable + 4, m_pSaveSecHdr, nSecNum * 40);
RtlCopyMemory(m_pTable + 4 + nSecNum * 40, &m_pImportAddr, 4);
RtlCopyMemory(m_pTable + 4 + nSecNum * 40 + 4, &nImpSize, 4);
RtlCopyMemory(m_pTable + 4 + nSecNum * 40 + 4 + 4, &m_pRelocAddr, 4);
RtlCopyMemory(m_pTable + 4 + nSecNum * 40 + 4 + 4 + 4, &nRelocSize, 4);
return true;
}bool CPacker::GetTable()
{ m_dwTableSize = nSecNum * 40 + 4 + 8 + 8;
m_pTable = new BYTE[m_dwTableSize];
RtlCopyMemory(m_pTable, &nSecNum, 4);
RtlCopyMemory(m_pTable + 4, m_pSaveSecHdr, nSecNum * 40);
RtlCopyMemory(m_pTable + 4 + nSecNum * 40, &m_pImportAddr, 4);
RtlCopyMemory(m_pTable + 4 + nSecNum * 40 + 4, &nImpSize, 4);
RtlCopyMemory(m_pTable + 4 + nSecNum * 40 + 4 + 4, &m_pRelocAddr, 4);
RtlCopyMemory(m_pTable + 4 + nSecNum * 40 + 4 + 4 + 4, &nRelocSize, 4);
return true;
}//绕过x64搜索导入表的节(空节)
strcpy((char*)m_newSecHdr[4].Name, ".imp");
m_newSecHdr[4].Misc.VirtualSize = GetAlign(0x10000, m_pNtHdr->OptionalHeader.SectionAlignment);
m_newSecHdr[4].VirtualAddress = m_newSecHdr[3].VirtualAddress + m_newSecHdr[3].Misc.VirtualSize;
m_newSecHdr[4].SizeOfRawData = 0;
m_newSecHdr[4].PointerToRawData = m_newSecHdr[3].PointerToRawData + m_newSecHdr[2].SizeOfRawData;
m_newSecHdr[4].Characteristics = IMAGE_SCN_MEM_EXECUTE | IMAGE_SCN_MEM_WRITE | IMAGE_SCN_MEM_READ;
//绕过x64搜索导入表的节(空节)
strcpy((char*)m_newSecHdr[4].Name, ".imp");
m_newSecHdr[4].Misc.VirtualSize = GetAlign(0x10000, m_pNtHdr->OptionalHeader.SectionAlignment);
m_newSecHdr[4].VirtualAddress = m_newSecHdr[3].VirtualAddress + m_newSecHdr[3].Misc.VirtualSize;
m_newSecHdr[4].SizeOfRawData = 0;
m_newSecHdr[4].PointerToRawData = m_newSecHdr[3].PointerToRawData + m_newSecHdr[2].SizeOfRawData;
m_newSecHdr[4].Characteristics = IMAGE_SCN_MEM_EXECUTE | IMAGE_SCN_MEM_WRITE | IMAGE_SCN_MEM_READ;
bool CPacker::WriteNewPe(CString strNewPe)
{ //创建文件
HANDLE hFile = CreateFile(strNewPe,
GENERIC_WRITE,
0,
NULL,
CREATE_ALWAYS,
FILE_ATTRIBUTE_NORMAL,
NULL);
//写入PE头
DWORD dwBytesWrited = 0;
WriteFile(hFile, m_pNewPeHdr, m_dwNewPeHdrSize, &dwBytesWrited, NULL);
//写入数据节
WriteFile(hFile, m_pComSec, m_dwComSecSize, &dwBytesWrited, NULL);
//写入代码节
WriteFile(hFile, m_pCodeSec, m_dwCodeSecSize, &dwBytesWrited, NULL);
//写入存放表数据节
WriteFile(hFile, m_pTableSec, m_dwTableSecSize, &dwBytesWrited, NULL);
CloseHandle(hFile);
return true;
}bool CPacker::WriteNewPe(CString strNewPe)
{ //创建文件
HANDLE hFile = CreateFile(strNewPe,
GENERIC_WRITE,
0,
NULL,
CREATE_ALWAYS,
FILE_ATTRIBUTE_NORMAL,
NULL);
//写入PE头
DWORD dwBytesWrited = 0;
WriteFile(hFile, m_pNewPeHdr, m_dwNewPeHdrSize, &dwBytesWrited, NULL);
//写入数据节
WriteFile(hFile, m_pComSec, m_dwComSecSize, &dwBytesWrited, NULL);
//写入代码节
WriteFile(hFile, m_pCodeSec, m_dwCodeSecSize, &dwBytesWrited, NULL);
//写入存放表数据节
WriteFile(hFile, m_pTableSec, m_dwTableSecSize, &dwBytesWrited, NULL);
CloseHandle(hFile);
return true;
}1.使用Release版（Debug会加地址有关代码）
2.不使用main函数，自己定义一个，放在链接器->高级->入口点（main不是程序真正入口点）
3.关掉代码生成->安全检查
4.关掉增强指令集
5.关掉全程序优化
1.使用Release版（Debug会加地址有关代码）
2.不使用main函数，自己定义一个，放在链接器->高级->入口点（main不是程序真正入口点）
3.关掉代码生成->安全检查
4.关掉增强指令集
5.关掉全程序优化
1.解压缩节表2里面的压缩数据
2.将解压缩数据覆盖到PE头处，连带着空节表1也被覆盖
3.还原节表、导入表、重定位表
1.解压缩节表2里面的压缩数据
2.将解压缩数据覆盖到PE头处，连带着空节表1也被覆盖
3.还原节表、导入表、重定位表
HMODULE GetKernel32(){ HMODULE hKer;
__asm {
mov eax, dword ptr fs:[0x30]
mov eax, dword ptr[eax + 0x0C]
mov eax, dword ptr[eax + 0x0C]
mov eax, dword ptr[eax]
mov eax, dword ptr[eax]
mov eax, dword ptr[eax + 0x18]
mov hKer, eax
}
return hKer;
}HMODULE GetKernel32(){ HMODULE hKer;
__asm {
mov eax, dword ptr fs:[0x30]
mov eax, dword ptr[eax + 0x0C]
mov eax, dword ptr[eax + 0x0C]
mov eax, dword ptr[eax]
mov eax, dword ptr[eax]
mov eax, dword ptr[eax + 0x18]
mov hKer, eax
}
return hKer;
}FARPROC MyGetProcAddress(HMODULE hMod, LPCSTR lpProcName) { IMAGE_DOS_HEADER* pDosHdr;
IMAGE_NT_HEADERS* pNTHdr;
IMAGE_EXPORT_DIRECTORY* pExpDir;
DWORD pAddrTbl;
DWORD pNameTbl;
DWORD pOrdTbl;
//解析dos头
pDosHdr = (IMAGE_DOS_HEADER*)hMod;
//nt头
pNTHdr = (IMAGE_NT_HEADERS*)(pDosHdr->e_lfanew + (DWORD)hMod);
//获取导出表
pExpDir = (IMAGE_EXPORT_DIRECTORY*)(pNTHdr->OptionalHeader.DataDirectory[0].VirtualAddress + (DWORD)hMod);
//导出函数地址表
pAddrTbl = (DWORD)(pExpDir->AddressOfFunctions + (DWORD)hMod);
//导出函数名称表
pNameTbl = (DWORD)(pExpDir->AddressOfNames + (DWORD)hMod);
//导出序号表
pOrdTbl = (DWORD)(pExpDir->AddressOfNameOrdinals + (DWORD)hMod);
//判断是序号还是名称
if ((int)lpProcName & 0xffff0000) {
//名称
int i = 0;
while (i < pExpDir->NumberOfNames) {
//获取名称地址
int nNameOff = (int)(*(DWORD*)(pNameTbl + i * 4) + (DWORD)hMod);
//字符串比较
if (((char*)nNameOff)[0] == 'G'&& ((char*)nNameOff)[1] == 'e'&& ((char*)nNameOff)[2] == 't'&&
((char*)nNameOff)[3] == 'P'&& ((char*)nNameOff)[4] == 'r'&& ((char*)nNameOff)[5] == 'o'&&
((char*)nNameOff)[6] == 'c'&& ((char*)nNameOff)[7] == 'A'&& ((char*)nNameOff)[8] == 'd'&&
((char*)nNameOff)[9] == 'd'&& ((char*)nNameOff)[10] == 'r'&& ((char*)nNameOff)[11] == 'e'&&
((char*)nNameOff)[12] == 's'&& ((char*)nNameOff)[13] == 's') {
//找到了, 从导出序号表取出函数地址下标
int nOrdinal = *(WORD*)(pOrdTbl + i * 2);
//从导出地址表，下标寻址，获取导出函数地址
int nFuncAddr = *(DWORD*)(pAddrTbl + nOrdinal * 4);
//不是转发
nFuncAddr += (int)hMod;
//返回地址
if (nFuncAddr != NULL) {
return (FARPROC)nFuncAddr;
}
}
i++;
}
}
else {
//序号
int nOrdinal = (DWORD)lpProcName - pExpDir->Base;
//从导出地址表，下标寻址，获取导出函数地址
int nFuncAddr = *(DWORD*)(pAddrTbl + nOrdinal * 4);
//返回地址
if (nFuncAddr != NULL) {
return (FARPROC)(nFuncAddr + (DWORD)hMod);
}
}
return 0;
}FARPROC MyGetProcAddress(HMODULE hMod, LPCSTR lpProcName) { IMAGE_DOS_HEADER* pDosHdr;
IMAGE_NT_HEADERS* pNTHdr;
IMAGE_EXPORT_DIRECTORY* pExpDir;
DWORD pAddrTbl;
DWORD pNameTbl;
DWORD pOrdTbl;
//解析dos头
pDosHdr = (IMAGE_DOS_HEADER*)hMod;
//nt头
pNTHdr = (IMAGE_NT_HEADERS*)(pDosHdr->e_lfanew + (DWORD)hMod);
//获取导出表
pExpDir = (IMAGE_EXPORT_DIRECTORY*)(pNTHdr->OptionalHeader.DataDirectory[0].VirtualAddress + (DWORD)hMod);
//导出函数地址表
pAddrTbl = (DWORD)(pExpDir->AddressOfFunctions + (DWORD)hMod);
//导出函数名称表
pNameTbl = (DWORD)(pExpDir->AddressOfNames + (DWORD)hMod);
//导出序号表
pOrdTbl = (DWORD)(pExpDir->AddressOfNameOrdinals + (DWORD)hMod);
//判断是序号还是名称
if ((int)lpProcName & 0xffff0000) {
//名称
int i = 0;
while (i < pExpDir->NumberOfNames) {
//获取名称地址
int nNameOff = (int)(*(DWORD*)(pNameTbl + i * 4) + (DWORD)hMod);
//字符串比较
if (((char*)nNameOff)[0] == 'G'&& ((char*)nNameOff)[1] == 'e'&& ((char*)nNameOff)[2] == 't'&&
((char*)nNameOff)[3] == 'P'&& ((char*)nNameOff)[4] == 'r'&& ((char*)nNameOff)[5] == 'o'&&
((char*)nNameOff)[6] == 'c'&& ((char*)nNameOff)[7] == 'A'&& ((char*)nNameOff)[8] == 'd'&&
((char*)nNameOff)[9] == 'd'&& ((char*)nNameOff)[10] == 'r'&& ((char*)nNameOff)[11] == 'e'&&
((char*)nNameOff)[12] == 's'&& ((char*)nNameOff)[13] == 's') {
//找到了, 从导出序号表取出函数地址下标
int nOrdinal = *(WORD*)(pOrdTbl + i * 2);
//从导出地址表，下标寻址，获取导出函数地址
int nFuncAddr = *(DWORD*)(pAddrTbl + nOrdinal * 4);
//不是转发
nFuncAddr += (int)hMod;
//返回地址
if (nFuncAddr != NULL) {
return (FARPROC)nFuncAddr;
}
}
i++;
}
}
else {
//序号
int nOrdinal = (DWORD)lpProcName - pExpDir->Base;
//从导出地址表，下标寻址，获取导出函数地址
int nFuncAddr = *(DWORD*)(pAddrTbl + nOrdinal * 4);
//返回地址
if (nFuncAddr != NULL) {
return (FARPROC)(nFuncAddr + (DWORD)hMod);
}
}
return 0;
}char szLoadLibrary[] = { 'L', 'o','a', 'd', 'L', 'i', 'b', 'r', 'a', 'r', 'y', 'A', '\0' };
pEnv->pfnLoadLibraryA = (PFN_LoadLibraryA)pEnv->pfnGetProcAddress(hKer, szLoadLibrary);
char szLoadLibrary[] = { 'L', 'o','a', 'd', 'L', 'i', 'b', 'r', 'a', 'r', 'y', 'A', '\0' };
pEnv->pfnLoadLibraryA = (PFN_LoadLibraryA)pEnv->pfnGetProcAddress(hKer, szLoadLibrary);
//有了LoadLibrary和GetProcAddress，就可以使用任意函数了
//获取解压缩相关函数
char szCab[] = { 'C','a','b','i','n','e','t', '\0' };
HMODULE hCab = pEnv->pfnLoadLibraryA(szCab);
char szCreateDecompressor[] = { 'C','r','e','a','t','e','D','e','c','o','m','p','r','e','s','s','o','r', '\0' };
pEnv->pfnCreateDecompressor = (PFN_CreateDecompressor)pEnv->pfnGetProcAddress(hCab, szCreateDecompressor);
char szDecompress[] = { 'D','e','c','o','m','p','r','e','s','s', '\0' };
pEnv->pfnDecompress = (PFN_Decompress)pEnv->pfnGetProcAddress(hCab, szDecompress);
char szVirtualAlloc[] = { 'V','i','r','t','u','a','l','A','l','l','o','c', '\0' };
pEnv->pfnVirtualAlloc = (PFN_VirtualAlloc)pEnv->pfnGetProcAddress(hKer, szVirtualAlloc);
char szVirtualProtect[] = { 'V','i','r','t','u','a','l','P','r','o','t','e','c','t','\0' };
pEnv->pfnVirtualProtect = (PFN_VirtualProtect)pEnv->pfnGetProcAddress(hKer, szVirtualProtect);
//解压缩
LPBYTE pPEBuff = (LPBYTE)env.pfnVirtualAlloc(NULL, dwDeComSize, MEM_COMMIT, PAGE_READWRITE);
DECOMPRESSOR_HANDLE hDecompressor;
BOOL bSuccess = env.pfnCreateDecompressor(
COMPRESS_ALGORITHM_XPRESS_HUFF,
NULL,
&hDecompressor
);
DWORD dwDecompressedBufferSize = 0;
bSuccess = env.pfnDecompress(
hDecompressor,
pComData,
dwComSize,
pPEBuff,
dwDeComSize,
&dwDecompressedBufferSize
);
//有了LoadLibrary和GetProcAddress，就可以使用任意函数了
//获取解压缩相关函数
[招生]科锐逆向工程师培训(2024年11月15日实地，远程教学同时开班, 第51期)
最后于 2022-8-23 12:21
被橘喵Cat编辑
，原因：
|
|
|---|---|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
还没学64位汇编 
|
|
|
|
|
|
|
|
|
|
Roger
