From gbhackers.com
Network Firewalls acts as a fortification to keep the internal corporate network secure. Many people often think as it is protecting a device from incoming traffic. Most outbound connections are insecure without egress traffic filtering.
If Egress Traffic Filtering failed then attackers bypass firewall to command and control the external network
Egress filter out traffic leaving your network and restrict your internal users from getting off of your network and going anywhere they would like(Different Network).So, egress traffic filtering help in mitigating data exfiltration from your networked assets.
While performing the penetration test, companies do special exceptions to ports to prevent access to the outside Internet.So Egressbuster will test the effectiveness of egress filtering in an environment. Download EgressBuster Here