Security devices Internal security External security Viruses and other malicious software OVERVIEW
Firewall: System enforcing security policy between two Networks. SECURITY DEVICES
Proxy Server: Server acting as a proxy (an anonymous intermediary) for Network users. Security devices
Packet filter: Enables users to set criteria for allowed and disallowed packets. Security devices
Securing Network from internal threats like: Accessing information inappropriately. Accessing other users’ files. Impersonating other users. Performing criminal activities on systems. Packet “sniffing” on the Network. INTERNAL SECURITY
Account security File and directory permissions Practices and user education Internal security
Process of managing the user accounts enabled on the Network. Account security
To manage security: Remove the guest account. Rename the default name for the administrative account. Remove access to Network resources. Work closely with HR/legal departments. Review newly assigned permissions. Account security
To maintain password security: Get users to change their Network password regularly. Set the reuse policy. Have passwords that are at least eight characters long. Establish thresholds. Account security
Control access to files and directories by using built-in permissions. File and directory permissions
Generic directory roles: Create only Read only Change Full control File and directory permissions
Inform users what is expected of them in terms of security. Discuss security issues with new employees. Have users acknowledge their understanding. Periodically audit users’ security actions. Review the NOS’ security logs. Practice and user education
Process of securing the Network from external threats. EXTERNAL SECURITY
Types of threats: Front-door threats Back-door threats Denial of service External security
Arise when a user from outside the company finds a user password and logs on to the Network. Front-door threats
Solutions: Separate Network resources accessed from and outside the LAN. Control users accessing LAN from outside the LAN. Set up a separate remote access account for remote users. Set up user accounts to use dial-back. Change password when employee with broad access resigns. Front-door threats
Software or hardware bugs in the Network’s OS enabling an outsider to crack the Network’s security. Back-door threats
Solutions: Host the company’s web site on an external server. Implement a firewall router. Review security settings for the web server. Place web server for non-employees outside the firewall.
Attacks that deny service to the Network. Denial of service
Solutions: Keep various Network software “current”. Disallow Internet Control Message Protocol (ICMP) traffic service.
Denial of service Demilitarized Zone (DMZ): The area between computers placed between the firewall an connection to an external Network.