So you got a fresh new firewall, out of the box. You are done with the basic configuration, placed it into your network, connected the management interface to the management network (Either you have a dedicated management switch / infrastructure which promises a true out of band connectivity or you create a "pseudo" separate network using management VLANs).
Of course, it is already recommended to have a firewall protecting the management network, the since compromise on this network can directly lead to access to each of the devices, with catastrophic outcome. In spite of this, there are several management hardening steps that should be carried out to ensure that the firewall's management access is as secure as it can be.
- Disable telnet (TCP 21) and HTTP (TCP 80)
Telnet and HTTP send data in clear text and all it takes is a carefully crafted SPAN / RSPAN session to forward a copy of the communication to a remote machine where the captured traffic (including clear text passwords) can be sniffed.
- Allow SSH (TCP 22) and HTTPS (TCP 443)
Both SSH and HTTPS encrypt traffic and no matter how much traffic is sniffed.. it is close to impossible to decrypt the traffic unless you have a private key, which the attacker wouldn't have (unless the administrator is naive enough to leave it lying on an unattended PC or a public exposed S3 bucket)
- Valid certificate for HTTPS access to the firewall
Either generate a self-signed certificate for the firewall from the trusted source or install a public CA (certificate authority) certificate. Make sure that acceptable cipher and encryption levels are used.
- Allow communication from the trusted IP addresses
The firewall administrators should usually belong to a particular subnet in the office. Palo Alto provides an option to allow for a couple of IPs / subnets only to get management access to the firewall. For eg. if you permit only 10.1.1.0/24 to access the firewall for administration, no other IP address would be able to access the firewall.
- Change the default login credentials
The default username password for the website are : admin / admin. "admin" username is the default superuser account. Create another username with superuser privileges and delete the "admin" username.
- SNMP settings
Simple Network Management Protocol (SNMP) is known to have vulnerabilities and there are several ways in which they can be exploited. However, most real-time monitoring tools necessitate the use of SNMP protocol, which is more or less unavoidable. Make sure that the SNMP community string is fairly complex.
- Ensure 'Idle timeout' is less than or equal to 10 minutes for device management
Making the firewall administrator login after an idle timeout ensures that an unauthorized user cannot access the firewall when the administrator inadvertently forgets logging out of the firewall.
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