Cisco Anyconnect and Virtualbox don't go well together. The firewall blocks all traffic except what goes through the VPN. To allow traffic to virtualbox you need to run the following snippet on your OSX every time the VPN (re)connects. Yosemite not supported yet by this script.

fix_vagrant_connection_fukup_by_cisco_anyconnect.sh

#!/bin/bash

if [ `uname` != "Darwin" ]; then
  echo "Run this on OS X "
  exit 1
fi

# pre ask password
sudo -v
# Set firewall rules so connection to virtualbox functions for Maverics
sudo ipfw add 00002 allow all from any to any via vboxnet0
sudo ipfw add 00002 allow all from any to any via vboxnet1
sudo ipfw add 00002 allow all from any to any via vboxnet2

# For Yosemite same should be done with pf