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Re: Slow Cisco Vpn performance!
From: "Brock, Anthony - NET" <Anthony.Brock () OREGONSTATE EDU>
Date: Thu, 27 Sep 2007 16:26:30 -0700

We've encountered significant and varied issues with the last of the 4.8 and earlier 5.x clients. Fortunately, most of 
our clients have been fairly stable when using version However, we haven't had similar reports concerning 
speed. Are you using the old VPN 3K or the ASA as your concentrator?
Anthony Brock
Senior Network Security Engineer
Oregon State University - Network Engineering


        From: Michael Sana [mailto:msana () HPU EDU] 
        Sent: Wednesday, September 26, 2007 12:28 PM
        Subject: Re: [SECURITY] Slow Cisco Vpn performance!

        Aloha Christian,


        Although we are not experiencing that problem, you may want to consider upgrading your Cisco VPN client to 
version 5.  Cisco recently released a security advisory regarding local privilege escalation vulnerabilities in older 
versions.   Although in your situation the users actually own the machines (and probably have local admin rights), you 
may have some users with university owned equipment that don't have privileged access.  We took things a step further 
by setting our configuration to only allow access with the newest designated VPN client to prevent users with older 
versions from logging in.


        Here is a summary of the advisory:


        Two vulnerabilities exist in the Cisco VPN Client for Microsoft Windows that may allow unprivileged users to 
elevate their privileges to those of the LocalSystem account. 

        A workaround exists for one of the two vulnerabilities disclosed in this advisory. 

        Cisco has made free software available to address these vulnerabilities for affected customers. 

        The actual advisory can be found here:



        Hope this helps...



        From: Christian Hroux [mailto:Christian.Heroux () ETSMTL CA] 
        Sent: Wednesday, September 26, 2007 7:46 AM
        Subject: [SECURITY] Slow Cisco Vpn performance!


        Hello !


                    We use Cisco VPN concentrator and most employees use the vpn with their own pc at home.  This might 
be a security risk and also a situation much harder to support but we mitigate de risk by limiting the vpn access to 
some port and inspecting traffic with IPS. Some users have reported very slow performance only when using university 
resources through the VPN.  All the test point out to the cisco vpn client  4.8  we use on windows XP. The only way to 
improve speed was to optimize windows XP TCP/IP stack with  http://www.speedguide.net/files/TCPOptimizer.exe in  the 
user`s pc. 


                    This doesn`t seem to be MTU related issue since we varied this parameter during test with the user 
who was having problem. 


                    Let me know off line if you had that kind of complaint from user.


        Christian Héroux 

        Bacc Ing. ÉTS, M. Ing. Poly, étudiant MBA HEC, Ing jr.


        Analyste de l'informatique 

        (Sécurité réseau & Télécom)

        Section systèmes, infrastructures et télécommunications

        École de Technologie Supérieure

        1100 rue Notre-Dame ouest

        Montréal, Québec

        H3C 1K3

        Tél : 396-8800 (7863)


         "Network design is 50 percent technology, 50 percent diplomacy, 50 percent magic"



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