Wednesday, March 25, 2009

Securing your network

An attacker looks for poorly configured network devices and exploit.

High-Level Network Threats

  1. Information gathering

  2. Sniffing

  3. Spoofing

  4. Session Hijacking

  5. Denial of Service

Information gathering


Information gathering can reveal detailed information about network topology,System configuration, and network devices.

Sniffing :

Sniffing is an act of network monitoring for traffic data.There are lot many packet sniffing tools are available to monitor the network.(Ex :ethereal)

Spoofing :

Spoofing means hide one's own identity. A fake source address is used for attack the target.

Session Hijacking:

The session hijacking, also known as man in the middle attacks, the attacker uses an
application that masquerades as either the client or the server.

Denial of Service:

A Denial of Service attack is the act of denying users to access the server or services.

Snapshot of a Secure Network:

Router :

  • Patches and Updates of Router operating system is patched with up-to-date software.

Protocols :

  • Unused protocols and ports are blocked.
  • Ingress and egress filtering is implemented.
    ICMP traffic is screened from the internal network.
  • TTL expired messages with values of 1 or 0 are blocked (route tracing is
    disabled).
  • Directed broadcast traffic is not forwarded.
  • Large ping packets are screened.
  • Routing Information Protocol (RIP) packets, if used, are blocked at the outermost router.

Administrative access:

  • Unused management interfaces on the router are disabled.
  • A strong administration password policy is enforced.
  • Static routing is used.
  • Web-facing administration is disabled

Services:

  • Unused services are disabled.

Auditing and Logging :

  • Logging is enabled for all denied traffic.
  • Logs are centrally stored and secured.
  • Auditing against the logs for unusual patterns is in place.

Intrusion detection :

  • IDS is in place to identify and notify of an active attack.

Network ACLs :

  • The network is structured so ACLs can be placed on hosts and networks.







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