Tag Archives: vpn

Problems with FortiClient and no traffic after succesful connection

I have just help a customer, with a problem with his FortiClient.
The Forticlient did connect successful, and everything looks good, but there are no traffic iis recieved.

The OS of the customer where Windows 11.

The solutions where quite simple, just uninstall this microsoft update: KB2693643
Read more about the error here: https://community.fortinet.com/t5/FortiClient/Troubleshooting-Tip-VPN-SSL-connected-but-no-IP-address-in/ta-p/248143

Windows 8 and Microsoft VPN problems

Today i have the problem where a Windows 8 machine, won’t connect to Microsoft VPN server.

The problems was that MSChapV2 was disabled on the client.
Please find this under Security and Allowed these protocols.

The error message I got from both the VPN servers and the client was:

Server:
The following error occurred in the Point to Point Protocol module on port: VPN2-9, UserName: XXXXX\XX. The connection was prevented because of a policy configured on your RAS/VPN server. Specifically, the authentication method used by the server to verify your username and password may not match the authentication method configured in your connection profile. Please contact the Administrator of the RAS server and notify them of this error.

Client:
Error 815: The connection was prevented because of a policy configured on your RAS/VPN server. Specifically, the authentication method used by the server to verify your username and password may not match the authentication method configured in your connection profile. Please contact the Administrator of the RAS server and notify them of this error.

Please see more here: http://jermsmit.com/windows-8-vpn-error-812/

Decrypt Cisco VPN group password

I have a customer how has broken his Cisco VPN Client profiles. But the group password encrypted was still fine.

So I found out that it was pretty easy to crack this encryption.

The algorithm
The algorithm which is used to encrypt a given user/group password is shown below (for further details just consult the source code):

  • The current date as a string is retrieved (e.g. Mon Sep 19 20:00:00 2005)
  • Then a SHA-1 Hash h1 is computed (20 Bytes)
  • h1 is modified and a new Hash h2 is calculated
  • h1 is again modified and h3 is calculated
  • the 3DES key is made of h2 and the first 4 bytes of h3
  • The password is encrypted using 3DES in CBC Mode. The IV consists of the first 8 bytes from h1.
  • The algorithm computes a last hash h4 from the encrypted password
  • The key “enc_UserPassword” in our profile file now looks like this: h1|h4|encrypted password

Jan Newger has made a programs witch can crack the password automatically, you can download it here: newgre.net/passwordrevealer#download

OpenVPN problems with dhcp

If you are using openvpn, and have a windows XP as Client, and have some troubles with dhcpclient

Mon Aug 01 11:34:29 2005 Route: Waiting for TUN/TAP interface to come up…
Mon Aug 01 11:34:30 2005 TEST ROUTES: 0/0 succeeded len=-1 ret=0 a=0 u/d=down
Mon Aug 01 11:34:30 2005 Route: Waiting for TUN/TAP interface to come up…
Mon Aug 01 11:34:31 2005 TEST ROUTES: 0/0 succeeded len=-1 ret=0 a=0 u/d=down
Mon Aug 01 11:34:31 2005 Initialization Sequence Completed With Errors (see http://openvpn.net/faq.html#dhcpclientserv )

Please try this fix:
Go to properties of you tap-adapter, go to avanced, then go to Media Status, put that on allways connected.