Anthrax - The Outsider

of these sleepy ports, dusted off the cobwebs and plugged in using the backdoor created by his tiny mail-borne program.

Connecting directly to a port created some problems, because the system wouldn't recognise certain keystrokes from the port, such as the return key. For this reason, Anthrax had to create an account for himself which would let him telnet to the site and login like any normal user. To do this, he needed root privileges in order to create an account and, ultimately, a permanent backdoor into the system.

He began hunting for vulnerabilities in System X's security. There was nothing obvious, but he decided to try out a bug he had successfully used elsewhere. He had first learned about it on an international phone conference, where he had traded information with other hackers and phreakers. The security hole involved the system's relatively obscure load-module program. The program added features to the running system but, more importantly, it ran as root, meaning that it had a free run on the system when it was executed. It also meant that any other programs the load-module program called up also ran as root. If Anthrax could get this program to run one of his own programs - a little Trojan - he could get root on System X.

The load-module bug was by no means a sure thing on System X. Most commercial systems - computers run by banks or credit agencies, for example - had cleaned up the load-module bug in their Sunos computers months before. But military systems consistently missed the bug. They were like turtles - hard on the outside, but soft and vulnerable on the inside. Since the bug couldn't be exploited unless a hacker was already inside a system, the military's computer security officials didn't seem to pay much attention to it. Anthrax had visited a large number of military systems prior to System X, and in his experience more than 90 per cent of their Sunos computers had never fixed the bug.

With only normal privileges, Anthrax couldn't force the load-module program to run his backdoor Trojan program.