Harold F. Tipton
Managing computer and network security programs has become an increasingly difficult and challenging job. Dramatic advances in computing and communications technology during the past five years have redirected the focus of data processing from the computing center to the terminals in individual offices and homes. The result is that managers must now monitor security on a more widely dispersed level. These changes are continuing to accelerate, making the security managers job increasingly difficult.
The information security manager must establish and maintain a security program that ensures three requirements: the confidentiality, integrity, and availability of the companys information resources. Some security experts argue that two other requirements may be added to these three: utility and authenticity (i.e., accuracy). In this discussion, however, the usefulness and authenticity of information are addressed within the context of the three basic requirements of security management.
Confidentiality is the protection of information in the system so that unauthorized persons cannot access it. Many believe this type of protection is of most importance to military and government organizations that need to keep plans and capabilities secret from potential enemies. However, it can also be significant to businesses that need to protect proprietary trade secrets from competitors or prevent unauthorized persons from accessing the companys sensitive information (e.g., legal, personnel, or medical information). Privacy issues, which have received an increasing amount of attention in the past few years, place the importance of confidentiality on protecting personal information maintained in automated systems by both government agencies and private-sector organizations.
Confidentiality must be well defined, and procedures for maintaining confidentiality must be carefully implemented, especially for standalone computers. A crucial aspect of confidentiality is user identification and authentication. Positive identification of each system user is essential to ensuring the effectiveness of policies that specify who is allowed access to which data items.
Threats to Confidentiality
Confidentiality can be compromised in several ways. The following are some of the most commonly encountered threats to information confidentiality:
A hacker is someone who bypasses the systems access controls by taking advantage of security weaknesses that the systems developers have left in the system. In addition, many hackers are adept at discovering the passwords of authorized users who fail to choose passwords that are difficult to guess or not included in the dictionary. The activities of hackers represent serious threats to the confidentiality of information in computer systems. Many hackers have created copies of inadequately protected files and placed them in areas of the system where they can be accessed by unauthorized persons.
A masquerader is an authorized user of the system who has obtained the password of another user and thus gains access to files available to the other user. Masqueraders are often able to read and copy confidential files. Masquerading is a common occurrence in companies that allow users to share passwords.
Unauthorized User Activity
This type of activity occurs when authorized system users gain access to files that they are not authorized to access. Weak access controls often enable unauthorized access, which can compromise confidential files.
Unprotected Downloaded Files
Downloading can compromise confidential information if, in the process, files are moved from the secure environment of a host computer to an unprotected microcomputer for local processing. While on the microcomputer, unattended confidential information could be accessed by authorized users.
Local Area Networks
LANs present a special confidentiality threat because data flowing through a LAN can be viewed at any node of the network, whether or not the data is addressed to that node. This is particularly significant because the unencrypted user IDs and secret passwords of users logging on to the host are subject to compromise as this data travels from the users node through the LAN to the host. Any confidential information not intended for viewing at every node should be protected by encryption.
Trojan horses can be programmed to copy confidential files to unprotected areas of the system when they are unknowingly executed by users who have authorized access to those files. Once executed, the Trojan horse becomes resident on the users system and can routinely copy confidential files to unprotected resources.
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