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One of the essential features of the application-level firewall is that it allows the network administrator to monitor a log of activities that take place at the firewall. This log can be used to identify potential breaches of security and to monitor resource usage.

A recent rash of network break-ins has been accomplished by IP-spoofing. IP-spoofing takes advantage of the UNIX OS, which erroneously presumes that anyone who logs in to a server using a previously approved TCP/IP address must be an authorized user. By altering the source IP, someone can spoof the firewall into believing a packet is coming from a trusted source. To combat this problem, many firewalls reject all packets originating from the external network and carrying an internal source IP.

SECURE INTERFACES

The secure interfaces level of security is rather sophisticated, somewhat akin to installing a new form of support beams in a house. Secure interfaces are software programs that allow for additional security checks in the network interface. Several companies offer these interfaces, most of which work with the various Web browsers as well as with Web server software. The most common secure interfaces are Netscape Communications Corp.’s SSL and S-HTTP.

SSL

SSL sits between TCP/IP and HTTP or other protocols such as SNMP or FTP. It provides privacy, authentication, and data integrity. MCI is one of the largest SSL users, employing the interface in InternetMCI. Other users include First Data Card Services (the world’s largest credit-card authorization firm), First Interstate, Old Kent, Bank of America, Norwest Card Services, as well as MasterCard International.

S-HTTP

S-HTTP extends HTTP to allow both the client and the server to negotiate various levels of security based on public-key encryption and provides encryption, authentication, and digital-signature features. It can also distinguish the origin of a particular document on any server. It was created by Terisa Systems, a joint venture between RSA Data Security and Enterprise Integration Technologies. S-HTTP’s strengths include its availability and flexibility.

Both the SSL and S-HTTP have been competing to become the standard secure interface for commercial sites on the Web. To head off the competition, Terisa Systems released a developers’ tool kit supporting both standards. Many other secure interfaces also exist, each with its own set of features.

LEGAL ISSUES

Many companies overlook the potential legal issues associated with connecting to the World Wide Web. The press has focused attention on many of these issues, including the availability of child pornography, boot-legged software, and ease of infringement of copyright laws. Managers should be aware of these potential dangers and take measures to protect employees and enterprises from lawsuits and loss of valuable copyrighted data.

This layer of security is comparable to household plumbing, which allows for unwanted items to be flushed away. For example, if FTP access to the server is allowed, network administrators should consider either prohibiting external users from placing files on the server or frequently purging files off the server. This guards against unwanted guests using the server as a clearing house for pirated software.

One well-publicized case of such an incident occurred at Florida State University, where unknown individuals employed a seldom-used computer as a storage facility for pirated software. It is not implausible that the owners of the server may be found liable for what resided on the computer, regardless of whether they had knowledge about it, and be brought to court on copyright infringement charges.

To curb access to sexually explicit materials, many companies are restricting access to a variety of UseNet groups. Although this practice may cut off the source of some illicit materials, users have other ways of gaining access to such materials. Companies cannot monitor the actions of all employees, but they may be able to reduce the likelihood of access to inappropriate sites by educating employees on what type of behavior will not be tolerated and aggressively enforcing such stances.

Employees also need to be educated on copyright laws. Although it is fairly well known that copying commercial, nonshareware, computer programs is illegal, other forms of copyright infringement are less obvious. Downloading a copy of a favorite song or distributing an article found on the network without permission may violate copyright laws.

Companies need to be concerned not only with what employees obtain but also with what they post outside the company. Employees may unwittingly release strategic information over the Internet, thereby jeopardizing data or potential profits. The only way to guard against such situations is through employee education that also encourages people to contact their manager, in-house counsel, or network administrator when they have questions.

CONCLUSION

The field of security and the threats to a corporate network will always be changing. The first step managers can take to secure a corporate network is to understand the range of security issues associated with Internet and Web access. The desired level of security must then be determined and security measures implemented.

Security needs to be viewed as a holistic process, because it is only as strong as its weakest link. Remaining aware of new developments in the field and continually adjusting security measures is one way of meeting the changing risks inherent on the Internet.

Some of the more recent yet still uncommon developments include HERF guns and EMPT bombs. Both of these threats can wipe out an entire data center, and the only way to be protected from them is to put corporate servers and data sources underground and secured in heavy paneling.

By monitoring server logs, staying alert to new security hazards, and altering the security system as needed, companies may be able to deter unwanted guests from visiting the corporate network. Organizations must also have adequate back-up plans that speed up recovery from the potentially devastating damages resulting from a successful security breach.


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