[KA Advisory 0411291] IPCop Cross Site Scripting Vulnerability in "proxylog.dat"

[Kurczaba Associates advisories <advisories () kurczaba com>]

IPCop Cross Site Scripting Vulnerability in "proxylog.dat"
http://www.kurczaba.com/html/security/0411291.htm
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Overview:
"IPCop implements existing technology, secure programming practices and outstanding new concepts to make it ‘the’ Linux 
Distribution for protecting single home computers, to large corporate networks from intrusions and attacks." 
-http://www.ipcop.org

Vendor:
IPCop (http://www.ipcop.org)

Affected Systems/Configuration:
1.4.1, possibly older versions

Vulnerability/Exploit:
A Cross Site Scripting vulnerability has been found in the IPCop web interface. The "proxylog.dat" page allows the 
IPCop administrators to review browsed websites that have been processed through Squid. By creating a specially crafted 
HTTP request, it is possible to inject script code into the "proxylog.dat" page. The variables "$url" and "$part" are 
not sanitized before being sent to the user. When the administrators view the page, the script code will be executed.

Proof of Concept:
The following HTTP request example will cause script injection into the proxy log:
-----START PoC-----
GET /<script>alert('XSS_PoC')</script> HTTP/1.1
Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, application/vnd.ms-excel, application/vnd.ms-powerpoint, 
application/msword, */*
Accept-Language: en-us
Accept-Encoding: gzip, deflate
User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1)
Host: example.com
Connection: Close


-----END PoC-------

         
Workaround:
1) Open /home/httpd/cgi-bin/logs.cgi/proxylog.dat
2) Locate the following text: unless (length($part) < 60) { $part = "${part}..."; }
3) Insert the following five lines below:
#Filter out < and >
$url =~s/</&lt;/g;
$part =~s/</&lt;/g;
$url =~s/>/&gt;/g;
$part =~s/>/&gt;/g;      

Date Discovered:
November 29, 2004

Severity:
Low

Credit:
Paul Kurczaba
Kurczaba Associates