The default shipping configuration of Teamwork Cloud is not a hardened configuration.
When hardening an installation, there are variables that can render the installation inoperative, such as incompatibility of the supported ciphers in a certificate and the supported ciphers in the hardened configuration.
Furthermore, the default configurations assume that the deployment is behind a secure infrastructure, and therefore required ports are globally allowed.
Since some of Teamwork Cloud's infrastructure relies on available components, newly discovered vulnerabilities need to be mitigated during the life-cycle of the installation.
Below, we will cover the potentially exploitable vulnerabilities of the different components, as well as various steps to mitigate depending on the policies of the deploying organization.
Cassandra Port Access
When installing on Linux using our deployment scripts, all of the ports required by Cassandra for inter-node communication, as well as for the Teamwork Cloud nodes to communicate with Cassandra nodes are opened globally. This configuration is deployed mostly to facilitate testing of the environment upon installation, prior to taking any measures to harden the installation. If we check the firewall upon installation, we will see an output similar to the one below:
Code Block
# firewall-cmd --list-all
public (active)
target: default
icmp-block-inversion: no
interfaces: eth0
sources:
services: cassandra lmadmin ssh twcloud
ports:
protocols:
masquerade: no
forward-ports:
source-ports:
icmp-blocks:
rich rules:
In our deployment we create a firewall service definition to facilitate management of the rules. This file is located in/etc/firewalld/services/cassandra.xml, and contains the following:
The first step in securing Cassandra is to limit traffic only to Cassandra and Teamwork Cloud Nodes. In the example below, we have a single node Cassandra/Teamwork Cloud installation, with its IP address set to 10.254.254.56.
As can be seen below, the firewall configuration has been modified to only allow access from itself.
Code Block
# firewall-cmd --list-all
public (active)
target: default
icmp-block-inversion: no
interfaces: eth0
sources:
services: lmadmin ssh twcloud
ports:
protocols:
masquerade: no
forward-ports:
source-ports:
icmp-blocks:
rich rules:
rule family="ipv4" source address="10.254.254.56" service name="cassandra" accept
The process to follow is to remove the general firewall allowance to the Cassandra service. After that, we want to ensure that if direct port rule assignments were made, they are removed. Finally, we want to create a set of rich rules which will allow access only to the required nodes.
If your deployment consists of a single-node or multi-node cluster where both Teamwork Cloud and Cassandra reside on the same nodes, we can automate this process by using the following script.
Code Block
title
harden_cassandra_ports.sh
#!/bin/bash
echo "Hardening Cassandra Ports"
echo "Creating Cassandra firewall service profile"
cat <<EOF | tee /etc/firewalld/services/cassandra.xml &> /dev/null
<?xml version="1.0" encoding="utf-8"?>
<service version="1.0">
<short>cassandra</short>
<description>cassandra</description>
<port port="7000" protocol="tcp"/>
<port port="7001" protocol="tcp"/>
<port port="9042" protocol="tcp"/>
<port port="9160" protocol="tcp"/>
<port port="9142" protocol="tcp"/>
</service>
EOF
echo "Removing existing firewall rules on the cassandra ports or service profile"
sleep 5
zone=$(firewall-cmd --get-default) &> /dev/null
firewall-cmd --zone=$zone --remove-port=7000/tcp --permanent &> /dev/null
firewall-cmd --zone=$zone --remove-port=7001/tcp --permanent &> /dev/null
firewall-cmd --zone=$zone --remove-port=7199/tcp --permanent &> /dev/null
firewall-cmd --zone=$zone --remove-port=9042/tcp --permanent &> /dev/null
firewall-cmd --zone=$zone --remove-port=9160/tcp --permanent &> /dev/null
firewall-cmd --zone=$zone --remove-port=9142/tcp --permanent &> /dev/null
firewall-cmd --zone=$zone --remove-service=cassandra --permanent &> /dev/null
echo "Creating ruch rules for Cassandra nodes discovered via nodetool gossipinfo"
set -f
local_list=($(nodetool gossipinfo | grep '/' | cut -f 2 -d /))
set +f
for i in "${local_list[@]}" ; do
cmd=" firewall-cmd --zone=$zone --add-rich-rule='rule family=\"ipv4\" source address=\"$i\" service name=\"cassandra\" accept' --permanent &> /dev/null"
echo $cmd
eval $cmd
done
firewall-cmd --reload &> /dev/null
The above script is structured in such a way that it will output the rich rule commands to the screen to facilitate copying and modifying to add nodes, which is needed if you have Teamwork Cloud nodes which are not part of the Cassandra cluster.
The above script should be executed on all nodes of a multi-node Cassandra cluster, with all nodes being in an operational state.
Windows Users: Create firewall rules restricting access on the aforementioned ports only to authorized nodes - Cassandra nodes and Teamwork Cloud Nodes.
Replication Strategy
Teamwork Cloud presently does not support Multi-DC replication strategies. As such, the environment must be configured with SimpleStrategy.
Cassandra Authentication
By default, Cassandra is deployed with the AllowAllAuthenticator. This authenticator, as the name implies, is an anonymous authenticator which performs no checks.
If you require authenticated connections, you will need to make changes to yourcassandra.yamland change the authenticator to PasswordAuthenticator. If you are running a multi-node Cassandra cluster, you need to change the replication factor of the system_auth keyspace.