Practical UNIX and Internet Security, 3rd Edition

Can You Trust Your Suppliers?

Your computer does something suspicious. You discover that the modification dates on your system software have changed. It appears that an attacker has broken in, or that some kind of virus is spreading. So what do you do? You save your files to backup tapes, format your hard disks, and reinstall your computer’s operating system and programs from the original distribution media.

Is this really the right plan? You can never know. Perhaps your problems were the result of a break-in. But sometimes, the worst is brought to you by the people who sold you your hardware and software in the first place.

Hardware Bugs

In 1994, the public learned that Intel Pentium processors had a floating-point problem that infrequently resulted in a significant loss of precision when performing some division operations. Not only had Intel officials known about this, but apparently they had decided not to tell their customers until after there was significant negative public reaction.

Several vendors of disk drives have had problems with their products failing suddenly and catastrophically, sometimes within days of being initially used. Other disk drives failed when they were used with Unix, but not with the vendor’s own proprietary operating system. The reason: Unix did not run the necessary command to map out bad blocks on the media. Yet these drives were widely bought for use with the Unix operating system.

Furthermore, there are many cases of effective self-destruct sequences ...