Tuesday, September 28, 2010

Securing HP Procurve Switches (or how to placate Auditors)

I was recently approached by an organization who suffered through an IT Systems and Security Audit.  Needless to say the audited highlighted a couple of holes in their system, and I was tasked with implementing the audit recommendations.  Part of my scope of work included securing their HP Procurve switches, this post will outline a couple of best-practices when securing your network equipment.  It is by no means exhaustive, but it should provide you with a good baseline.  All instructions assume you're logged into the switch and at the (config)# prompt

Defaults Configurations and Secure Alternatives

Telnet vs SSH
Telnet is an antiquated and insecure protocol; it sends all traffic across the wire in clear text. This includes user
names and passwords. Any attacker may eavesdrop on a Telnet session and obtain credentials.  Below are the commands detailing how to disable Telnet and and implement SSH.
  1. crypto key generate ssh
  2. ip ssh
  3. no telnet-server
ProCurve switches and routers can, by default, be configured through the web interface. The HTTP
interface has the same limitations as Telnet. It is therefore recommended that the HTTPS interface be configured and the HTTP interface be disabled, like so:
  1. crypto key generate cert 1024
  2. web-management ssl
  3. no web-management plaintext
TFTP client and server should be disabled as they do not require any authentication. Secure File
Transfer Protocol (SFTP) and Secure Copy Protocol (SCP) are part of the SSH protocol suite. As such provide an encrypted session using public/private keys between client and server just like
SSH.  You configure it like so:
  1. crypto key generate ssh
  2. ip ssh filetransfer 
  3. no tftp server
  4. no tftp client
SNMPv1/2c vs. SNMPv3
SNMP version 2 is enabled by default.  SNMPv2 community names are sent across the network as clear text (similiar to Telnet).  SNMP version 3 overcomes these weaknesses via encryption.  Here's how to configure it:
  1. snmpv3 enable
  2. snmpv3 only
If, for whatever reason, you cannot run SNMP v3, it is possible to run SNMP v2 in restricted mode, i.e. provide Read-Only access to your switch:
  1. snmp-server community restricted 
It is also possible to completely disable SNMP altogether:
  1. no snmp-server enable
Authorised IP Managers
It’s possible to restrict IP access to the switch to certain management IP's only.  This is configured via the following command:
  1. ip authorized-manager <IP address> mask  
Whilst not the be-all and end-all of security, the above should go a long way to ensure a reasonably secure base line for your HP Procurve network equipment.

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