Arbitrary File Download Vulnerability in Opera Web Browser

Reported November 20, 2003, by ::Operash::.

VERSIONS AFFECTED

DESCRIPTION

A newly discovered vulnerability in Opera for Windows can result in the arbitrary download of code to a path of an attacker’s choosing on the vulnerable system. This vulnerability is a result of the browser’s auto-install function, which executes when Opera receives an arbitrary file that contains the MIME-type "application/x-opera-configuration-XXXXX" or "application/x-opera-skin" from a remote server. Because the automatically saved file's name isn’t sufficiently sanitized, an attacker can save the file in any directory that he or she can specify with a relative path when the filename contains the illegal character string “..%5C.”
 

DEMONSTRATION

The discoverer has posted sample code demonstrating this vulnerability at this web site.

VENDOR RESPONSE

Opera has released version 7.23, which isn’t vulnerable to this problem.

CREDIT

Discovered by:: Operash ::.