Computer Security Computer Security as a principle; Computer Security in UNIX for specific; Conclusion.

Computer Security in General

Threats to Computer Security Errors and Omissions Employee Sabotage Loss of Physical and Infrastructure support Malicious Hackers

And More interesting ones………. Malicious Code Foreign Government Espionage –Industrial Espionage

malicious codes Virus: A code segment that replicates by attaching copies of itself to existing executables. The new copy of the virus is executed when a user executes the new host program. The virus may include an additional "payload" that triggers when specific conditions are met. For example, some viruses display a text string on a particular date. There are many types of viruses, including variants, overwriting, resident, stealth, and polymorphic.

Trojan Horse Trojan Horse: A program that performs a desired task, but that also includes unexpected (and undesirable) functions. Consider as an example an editing program for a multiuser system. This program could be modified to randomly delete one of the users' files each time they perform a useful function (editing), but the deletions are unexpected and definitely undesired!

Worm A self-replicating program that is self- contained and does not require a host program. The program creates a copy of itself and causes it to execute; no user intervention is required. Worms commonly use network services to propagate to other host systems.

Computer Security Program From a managerial viewpoint

An example of computer security program: An central computer security program How to be effective?

First…... Stable Program Management Function.

Second--- Stable Resource Base

What are remaining... Published Mission and Functions Statement Long-Term Computer Security Strategy. Intraorganizational Liaison and Liaison with External Groups

How to do if incident happens? A Incident Handling Capability

Five requirements for IHC: An understanding of the constituency it will serve; an educated constituency; a means of centralized communications; Expertise in the requisite technologies; Links to other groups to assist in incident handling.

One of the weakest links in security systems is Awareness, training and education of people

Three things to do…. Improving awareness of the need to protect system resources; developing skills and knowledge; Building in-depth knowledge.

Comparison of these three factors

Conclusion What a good security should be?

First: –Computer Security Supports the Mission of the Organization.

Second: Computer Security is an Integral Element of Sound Management

Third: –Computer Security Should Be Cost- Effective.

Fourth: –Computer Security Requires a Comprehensive and Integrated Approach.

And also: –Computer Security Should Be Periodically Reassessed.

References William Stallings: Operating Systems: Internals and Design Principles, Third Edition. Prentice Hall, Alvare,A. "How Crackers Crack Passwords or What Passwords to Avoid." Proceeding, UNIX Security Workshop II, August 1990 Artsy,Y.,ed.Newsletter of the IEEE Computer Society Technical Committee on Operating Systems, Winter S. Carl-Mitchell and John S. Quarterman, Building Internet Firewalls. UnixWorld; February, 1992; Shabbir J. Safdar. Giving Customers the Tools to Protect Themselves. USENIX Proceedings, UNIX Security Symposium III; September 1992.

And… Wietse Venema. TCP Wrapper: Network Monitoring,Access Control and Booby Traps. USENIX Proceedings,UNIX Security Symposium III; September David and Michelle Koblas. SOCKS. USENIX Proceedings, UNIX Security Symposium III; September J. David Thompson and Kate Arndt. A Secure Public Network Access Mechanism. USENIX Proceedings, UNIX Security Symposium III; September 1992.