Tried, Tested and Proven

Vulnerability title: Stored XSS in Symmetricom s350i

CVE: CVE-2014-5069
Vendor: Symmetricom
Product: s350i
Affected version: 2.70.15
Fixed version: N/A
Reported by: Mike Emery

Details:

It was discovered that data supplied to the web application was permanently stored and could be retrieved later by other users. This is a normal feature of many applications, however, in this instance the application failed to restrict the type of data that could be stored and also failed to sanitise it, meaning that it could not be safely rendered by the browser.

It was identified that any input which entered the system logs (including unauthenticated areas such as the username field on the login page) was susceptible.

The malicious content (in the case of the login page example) could then be viewed at the following URL:

http://192.168.224.51/controller/authlog.php

Note: This was not the only place in which cross-site scripting was identified. It appears that this issue is endemic due to the way in which the web application has been developed.

Impact:

An attacker could exploit this flaw to get active HTML or script code executed in an authenticated user’s browser. Cross-site Scripting may be used to perform attacks such as session hijacking by invoking the user’s browser to send information stored in their cookies (such as a session identification token) to an arbitrary location controlled by the attacker. Furnished with this information the attacker will be able to access the site, masquerading as the authenticated user who viewed the page containing the malicious code. The attacker would then be able to perform actions as the authorised user, subject to their role, which could include viewing sensitive data, modifying profile information and making transactions.

This vulnerability could also be leveraged in a phishing attack, whereby the attacker adds additional HTML code to create a false login page within the vulnerable page, which posts the data to a server controlled by the attacker. The attacker could then redirect the user back to the original server, thus giving the illusion that the login was secure and genuine. This could also be achieved by redirecting the user to a false login page on the attacker’s server rather than adding the code to a page that already exists. This is critical, because if the attacker could host a phishing website in a domain with a valid SSL certificate, there would be no way for a user to spot the attack.

A variation of the phishing attack described above would be to inject code to completely rewrite the genuine page, defacing the site and possibly having a detrimental impact on the reputation of the company.

Finally, an attacker could use Cross-site Scripting to exploit vulnerabilities within web browsers. The outcome of such an attack would depend on the exploits used, but in a worst case scenario the attacker could gain full control of a user’s computer. Once that had been achieved it would be trivial for the attacker to install a keystroke logger and gain access to applications via the usernames and passwords they had acquired.

Note: Whilst an attacker could just send a victim a page containing the exploit code and try to encourage them to view the content, they are more likely to be successful in convincing an individual to follow a link that comes from a site the user knows and trusts.

Exploit:

1) Attempt to login to the system over SSH as follows:


ssh '<script>alert(1)</script>'@192.168.224.51

2) View the following URL:

http://192.168.224.51/controller/authlog.php

Vendor status:

30/05/2014 Advisory created
10/06/2014 Vendor contacted
09/07/2014 Vendor contact reattempted
28/07/2014 CVE obtained and provisional release date set
13/08/2014 Final vendor contact initiated
20/08/2014 First vendor response
20/08/2014 Vendor advised of release date and more information on fix time
frame requested
28/08/2014 Vendor contacted to re-emphasise release dates as no response from
previous contact was received
29/08/2014 Vendor responded requesting a discussion before release. This was
not possible due to time zone differences
29/08/2014 Published
01/09/2014 In discussion with vendor following a period of non-response

Copyright:

Copyright © Portcullis Computer Security Limited 2014, All rights reserved worldwide. Permission is hereby granted for the electronic redistribution of this information. It is not to be edited or altered in any way without the express written consent of Portcullis Computer Security Limited.

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