OSEC

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Subject: Big Brother filename extension vulnerability
From: xternal (xternal1YAHOO.COM)
Date: Tue Jul 11 2000 - 18:11:39 CDT


versions affected: bb14h2 (current) and older

exploit:
        bbd listens for incoming connections on port 1984.
Using telnet or the bb client, it is possible to
connect and create a filename with an arbitrary
extension, as the extension is not rigorously checked.
 As this file is droped into a directory accessible
via the web server, any file extension that is parsed
server side can be abused. For example:

./bb 1.2.3.4 "status evil.php3 <?<system(\"cat
/etc/passwd\");?>"

will allow viewing of the /etc/passwd upon browsing to
http://1.2.3.4/bb/logs/evil.php3.
        

solutions:
        -Modify bbd.c to only allowed specified file
extensions(.disk, .proc ...)

        -Implement access restrictions via
$BBHOME/etc/security to minimize exposure to
vulnerabilities. Unfortunately, the default install
doesn't enable the security file.

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