JayK
January 5th, 2004, 09:43 AM
The first one is less serious
http://www.secunia.com/advisories/10523/
Arman Nayyeri has discovered a variant of the older showHelp() zone bypass vulnerability, which works in Internet Explorer with all current patches.
Websites can call the showHelp() function and open locally installed "CHM" files, which are compressed help files. These may contain references to system commands and can execute code with the privileges of the logged in user.
Normally, it isn't a problem that Internet Explorer allows websites to open locally installed "CHM" files as they are considered trusted.
However, other files can be treated as "CHM" files by using a special syntax with a double ":" appended to the file name combined with a directory traversal using the "..//" character sequence.
This can be exploited if a program such as WinAmp, XMLHTTP, ADODB stream or others allow websites to place files in a known location.
An example exploit has been published, which is capable of running arbitrary code on the system if WinAmp is installed in the default location.
The vulnerability has been confirmed in fully patched Internet Explorer 6 with WinAmp 5 installed.
Solution:
Disable active scripting support and enable it only for trusted sites.
Filter HTML pages with references to "showHelp()" using a HTTP proxy or firewall with content filtering capabilities.
Use another product.
The second is a stunner just announced on bugtraq, unfortunately I can't seem to access it now to post the link, but it basically allows another attacker to save and excute any link you click on.
http://www.secunia.com/advisories/10523/
Arman Nayyeri has discovered a variant of the older showHelp() zone bypass vulnerability, which works in Internet Explorer with all current patches.
Websites can call the showHelp() function and open locally installed "CHM" files, which are compressed help files. These may contain references to system commands and can execute code with the privileges of the logged in user.
Normally, it isn't a problem that Internet Explorer allows websites to open locally installed "CHM" files as they are considered trusted.
However, other files can be treated as "CHM" files by using a special syntax with a double ":" appended to the file name combined with a directory traversal using the "..//" character sequence.
This can be exploited if a program such as WinAmp, XMLHTTP, ADODB stream or others allow websites to place files in a known location.
An example exploit has been published, which is capable of running arbitrary code on the system if WinAmp is installed in the default location.
The vulnerability has been confirmed in fully patched Internet Explorer 6 with WinAmp 5 installed.
Solution:
Disable active scripting support and enable it only for trusted sites.
Filter HTML pages with references to "showHelp()" using a HTTP proxy or firewall with content filtering capabilities.
Use another product.
The second is a stunner just announced on bugtraq, unfortunately I can't seem to access it now to post the link, but it basically allows another attacker to save and excute any link you click on.