Threat Level: green Handler on Duty: Johannes Ullrich

SANS ISC: Deja-Vu: Cisco VPN Windows Client Privilege Escalation - SANS Internet Storm Center SANS ISC InfoSec Forums

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Deja-Vu: Cisco VPN Windows Client Privilege Escalation

Cisco released earlier today a bulletin regarding a vulnerability in the Cisco VPN client for Windows 7. The vulnerability is pretty simple: The client runs as a service, and all users logged in interactively have full access to the executable. A user could now replace the executable, restart the system and have the replacement running under the LocalSystem account.

The fix is pretty simple: Revoke the access rights for interactive users.

The interesting part : NGS Secure Research found the vulnerability, and released the details after Cisco released the patch [1]. The vulnerability is almost identical to one found in 2007 by the same company in the same product [2]

Very sad at times how some vendors don't learn. Lucky that at least companies like NGS appear to be doing some of the QA for them.


Johannes B. Ullrich, Ph.D.
SANS Technology Institute

I will be teaching next: Application Security: Securing Web Apps, APIs, and Microservices - SANSFIRE 2022


4506 Posts
ISC Handler
Jun 28th 2011
Actually, Cisco's bulletin for this was updated in March when the problem was actually fixed.

423 Posts
ISC Handler
Can someone explain this a bit. Since permissions are inherited for the most part, would any service executable residing in the Program Files directory be similarly vulnerable or did Cisco somehow modify the default permssions? Thanks in advance.

135 Posts

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