3 Mail server An mail server is typically a combination of processes running on a server with a large storage capacity – a list of users and rules, and the capability to receive, send and store emails and attachments Mail server software: Mdeamon, Exchange server 2003,…
4 Why use Exchange 2003 Backup and restore High availability Help migrating from older systems Security improvements Protection of e-mail
6 Exchange 2003 Mobile Capabilities ISAFirewall Wireless Network OWA clients (HTTP/HTML ) Pocket PC, Smartphone, third-party sync (HTTP/HTML) Outlook Mobile Access WAP 2.0, iMode (xHTML, cHTML ) Outlook clients (RPC/HTTP) Exchange 2003 Servers
7 The goal of attack Steal data Blackmail Launch bed for others attack Bragging rights Vandalism Demonstrate vulnerability/satisfy curiosity Damage company reputation Others?
8 Exchange 2003 and ISA 2006 Securing SMTP Traffic: SMTP-based attacks: – Invalid, overly long, or unusual SMTP commands to attack a mail server or to gather recipient information – Attacks against recipients by including malicious content, such as worms ISA Server protects mail servers by: – Enforcing compliance of SMTP commands with standards – Blocking disallowed SMTP commands – Blocking messages with disallowed attachment types, content, recipient or sender ISA Server can stop attacks before they reach your mail servers!! ISA Server can stop attacks before they reach your mail servers!!
9 Exchange 2003 and ISA 2006 RPC and Firewalls: Traditional Firewall – Open every port that RPC might use for incoming traffic ISA Firewall – Initial connection Only allows valid RPC traffic Blocks non-Exchange queries – Secondary connection Only allows connection to port used by Exchange Enforces encryption Traditional firewalls can’t provide secure RPC access ISA Server enables secure remote email access using Outlook
10 OWA and Traditional Firewalls Web traffic to OWA is encrypted – Standard SSL encryption – Security against eavesdropping and impersonation Limitation – Default OWA implementation does not protect against application layer attacks Exchange Web Server OWA Traffic Password Guessing Web Server Attacks SSL Tunnel Internet
11 How ISA Protects OWA Authentication – Unauthorised requests are blocked before they reach Exchange – Optional forms-based authentication prevents caching of credentials Inspection – Invalid HTTP requests or requests for non-OWA content are blocked – Inspection of SSL traffic before it reaches Exchange server Confidentiality – Ensures encryption of traffic over the Internet – Can prevent the downloading of attachments to client Web Server Attacks Password Guessing Exchange Server OWA Traffic SSL Tunnel Inspection Authentication Internet
14 Understanding the Need for Third- Party CAs can buy a certificate from a third-party certificate authority such as Verisign, Thawte, or one of many other enterprise certificate authorities validate that their customers are really who they say they are, and to generate the digital certificates that validate this for digital communications that require encryption, such as SSL
15 Installing a Third-Party CA on an OWA Server
16 Type of CA Enterprise root CA: highest-level certificate authority for an organization Enterprise subordinate CA: subordinate to an existing enterprise root CA, and must receive a certificate from that root CA to work properly Stand-alone root CA:similar to an enterprise CA, in that it provides for its own unique identity and can be uniquely configured