-- Corsaire Security Advisory --

Title: VMware ESX Server Cross Site Scripting issue
Date: 14.11.05
Application: VMware ESX prior to 2.5.2 upgrade patch 2
             VMware ESX prior to 2.1.2 upgrade patch 6
             VMware ESX prior to 2.0.1 upgrade patch 6
Environment: VMware ESX
Author: Stephen de Vries [stephen.de.vries@corsaire.com]
Audience: General distribution
Reference: c051114-002


-- Scope --

The aim of this document is to clearly define an issue that exists with 
the VMware ESX Server product [1] that will allow a remote attacker to 
inject arbitrary active scripting content, such as JavaScript, into a 
web session.


-- History --

Discovered: 11.11.05 (Stephen de Vries)
Vendor notified via client: 15.11.05
Vendor notified directly: 19.05.06
Document released: 01.06.06


-- Overview --

VMware ESX Server is described [1] as virtual infrastructure software 
for partitioning, consolidating and managing servers in mission-critical 
environments. 
 
The software provides a virtualization layer that allows multiple x86 
based operating systems to run on the same hardware concurrently.  The 
ESX Server product differs from other VMware products in that it does 
not require a "host" operating system to be provided by the user.  
Instead, it uses a custom x86 kernel as the host, along with a 
customised Linux operating system as a "console O/S". 
 
VMware ESX Server includes a number of network services and a web 
application, called the "VMware Management Interface" that can be used 
to perform remote administration of the system. 


-- Analysis --

The VMware ESX Server product provides a web application to perform 
management of the system.  One of the functions of this application is 
to allow administrative users to view log files, such as syslog, through 
a browser.  No encoding of syslog data is performed to ensure that HTML 
meta-characters are not interpreted by the browser.  This allows an 
attacker to inject HTML content, including JavaScript, into the syslog 
file where it would be rendered or executed when viewed through the 
Management Interface.  Since the raw syslog data is displayed between 
<div> tags, it is necessary to close the tag for a clean injection.  Two 
injection methods were detected: 
 
1.  An attacker could simply attempt to log in to the Management 
Interface with a username that contains the injection script, such as: 
 
</div><script>alert('XSS')</script> 
 
2.  An attacker could attempt to log in to the ftp server with a 
username containing a similar injection string. 
 
It should be noted that the ftp server is not enabled by default, 
however, the Management Interface is. 
 
This flaw could be used to conduct any number of Cross Site Scripting 
attacks [2], such as Session Hijacking, Cross Site Request Forgery or 
apparent falsification of the syslog data. 
 
The risk of this vulnerability is increased due to the fact that only 
administrative users have permission to view the syslog files through 
the Management Interface.  Should a Session Hijacking attack be 
successful, it would therefore likely yield administrative access. 


-- Recommendations --

Upgrade to a version of the VMware ESX product that does not exhibit 
this issue:

VMware ESX 2.5.2 upgrade patch 2 and later
VMware ESX 2.1.2 upgrade patch 6 and later
VMware ESX 2.0.1 upgrade patch 6 and later
 

-- CVE --

The Common Vulnerabilities and Exposures (CVE) project has assigned the 
name CVE-2005-3619 to this issue.  This is a candidate for inclusion in 
the CVE list (https://cve.mitre.org), which standardises names for 
security problems.


-- References --

[1] https://www.vmware.com/products/esx/ 
[2] https://www.aspectsecurity.com/topten/xss.html


-- Revision --

a. Initial release.
b. Minor edits.
c. Released.


-- Distribution --

The information contained within this advisory is supplied "as-is" with 
no warranties or guarantees of fitness of use or otherwise. Corsaire 
accepts no responsibility for any damage caused by the use or misuse of 
this information.


-- Disclaimer --

The information contained within this advisory is supplied "as-is" with 
no warranties or guarantees of fitness of use or otherwise. Corsaire 
accepts no responsibility for any damage caused by the use or misuse of 
this information.


-- About Corsaire --

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