Security is an even greater problem for
wireless networks, since radio signals travel through the open atmosphere
where they can be intercepted by individuals who are constantly on the move �
and therefore difficult to track down. Secondly, wireless solutions are, almost
universally, dependent on public-shared infrastructure where you have much less
control of, and knowledge about, the security discipline employed. Horror
stories of hackers scanning airwaves and siphoning off cellular ID numbers for
fraudulent use have become commonplace. Even pager messages are no longer safe.
Here are some examples of common security
breaches:
- Interception of law enforcement data on SMR,
private radio or CDPD networks by criminal elements
- Interception of credit card authorizations
over wireless networks
- Physical breach of security at unmanned base
stations or other communications centers.
- Interception of e-mail messages on wireless
internet connections
- Stealing of cellular airtime
While it may not be possible to make any system
completely secure, there are certain steps that can be and must be taken to
ensure that the risk of security breaches is minimized.
Sources of Security Leaks
Many local exchange carriers use microwave communications for their inter-LATA
calls. Since the frequencies used by carriers is public information, it is not
at all difficult for an intruder to intercept both voice and data transmissions.
Even with inter-exchange circuits increasingly
being converted to fiber, radio and satellite transmissions are still used by
many carriers. Network providers should be asked specifically what type of
circuits are used for traffic back-haul from base stations, and in particular
what circuits will be used in any proposed networking solution.
Tampering with Cellular NAMs as a
Security Leak
A common problem in the cellular industry is the theft of air time by
individuals who make cellular calls without paying for them. These people have
found a relatively easy way of pirating the numeric assignment numbers (NAMs) of
valid users. Even combinations of NAM plus MAN1 or MAN2 sequences are no longer
secure. PCS digital networks are somewhat more secure than analog cellular
networks.
Stealing Information
It is not uncommon for individuals intent on industrial espionage to scoop up
vast quantities of information by placing small scanners at appropriate
locations and searching with very powerful algorithms. Credit card numbers and
bank account numbers are among the most common types of information stolen.
While such an effort does require determination and planning on the part of
thieves, it should be remembered that often the law breaker is far more
motivated than is the person in charge of security. Security system designers
need to keep this in mind and to make their security arrangement as tight as the
technology and the budget will allow.
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