Unauthenticated remote code execution on D-Link ShareCenter products

Advisory Information
Title: Unauthenticated remote code execution on D-Link ShareCenter products
Release date: 08/02/2012
Last update: 08/02/2012
Credits: Roberto Paleari, Emaze Networks S.p.A.

Vulnerability Information
Class: Authentication bypass, remote code execution

Affected Software
We confirm the presence of the security vulnerabilities on the following products/firmware versions:
  • DNS-320, firmware version 2.00.1217.2010
  • DNS-320, firmware version 2.01.0512.2011
  • DNS-320, firmware version 2.02.0901.2011
  • DNS-320, firmware version 2.02.0923.2011
  • DNS-325, firmware version 1.01.1217.2010
Other models and firmware versions are probably also vulnerable, but they were not checked.

Vulnerability Details
D-Link ShareCenter devices suffer from a publicly-known authentication bypass issue that, according to an existing advisory, can be exploited to cause a Denial-of-Service.

In this advisory we shed some light over the impact of this issue. In particular, the device implements almost no authentication checks on HTTP requests for any existing CGI script (i.e., all the CGIs under the /cgi directory). As an example, an attacker may retrieve the device model & firmware version by accessing the following resources:
  • http:///cgi-bin/discovery.cgi
  • http:///cgi-bin/system_mgr.cgi?cmd=get_firm_v_xml
Besides information gathering, this vulnerability can be exploited to gain full control of the device. In particular, an undocumented functionality permits to execute arbitrary commands, displaying their output in the generated HTML page. As an example, to execute the "ls" command, an attacker can access the following URL:
  • http:///cgi-bin/system_mgr.cgi?cmd=cgi_sms_test&command1=ls
Even in this case, no authentication checks are performed.

Remediation
At the time of writing, we are not aware of an updated firmware that corrects the issue described in this advisory.

Report Timeline
  • 22/12/2011 - Initial vendor contact.
  • 27/12/2011 - Vendor replied.
  • 28/12/2011 - Emaze asks for a technical contact to discuss the details of the vulnerability. Publication date set to January 18th, 2012.
  • 02/01/2012 - No response from the vendor. The author re-sent the last e-mail.
  • 17/01/2012 - Still no reply from the vendor. The author re-sent the e-mail, again.
  • 31/01/2012 - Sent another e-mail to vendor, to inform about the intention to publicly disclose the vulnerability within February, 3rd.
  • 08/02/2012 - Still no reply. Disclosure.

Copyright
Copyright(c) Emaze Networks S.p.A. 2012, All rights reserved worldwide. Permission is hereby granted to redistribute this advisory, providing that no changes are made and that the copyright notices and disclaimers remain intact.

Emaze Networks has updated ipLegion, its vulnerability assessment platform, to check for this vulnerability. Contact info@emaze.net to have more information about ipLegion.

Disclaimer
Emaze Networks S.p.A. is not responsible for the misuse of the information provided in our security advisories. These advisories are a service to the professional security community. There are NO WARRANTIES with regard to this information. Any application or distribution of this information constitutes acceptance AS IS, at the user's own risk. This information is subject to change without notice.

No comments:

Post a Comment