Cisco VPN client password decrypt

I used cisco-decrypt to decrypt my Cisco VPN group password on Windows so I could use the Eindhoven University of Technology (TU/e) VPN in Ubuntu.

Tested on Linux Mint 10.

cisco-decrypt

• Upstream: http://www.unix-ag.uni-kl.de/~massar/bin/cisco-decode

• Local backup: cisco-decrypt and source cisco-decrypt.c

How to get the password from Windows

• Get the *.pcf file from

  C:\Program Files\Cisco Systems\VPN Client\Profiles
  

  If TU/e VPN: TUe-des.pcf.

• Extract encrypted group password from the !enc_GroupPwd key. Looks something like a 112 character uppercase hexadecimal number.

• cisco-decrypt depends on libgcrypt11 so install this first:

  $ sudo apt-get install libgcrypt11
  

• Use cisco-decrypt to decrypt the password:

  $ cisco-decrypt [encrypted-group-password]
  

• Voila, now we have the group password

Configure vpnc for TU/e VPN

• Install network-manager-vpnc-gnome:

  $ sudo apt-get install network-manager-vpnc-gnome
  

• Go to NetworkManager -> VPN Connections -> Configure VPN -> Add.

  Use "vpnc" and click "Create ...". Use these details and click on Apply:

Configuration

Connection name: TU/e VPN
Connect automatically off

VPN

Gateway: vpn.tue.nl
Group name: des
User password -> Saved
User password: TU/e password
Group password -> Saved
Group password: (use cisco-decrypt, see above)
User name: TU/e s-number
Domain:
Encryption method: Weak (use with caution)
NAT traversal: NAT-T when available (default)

IPv4 Settings

Method: Automatic (DHCP)