Doctor Who_ Blue Box - Kate Orman [21]
We sat there for maybe a quarter of an hour, listening to the modem dial and dial again and again. The Doctor explained that his program was set up to call numbers that he knew were allocated to TLA’s headquarters. Presumably he’d poked around in Ma Bell’s computers for a few hints, although he might have guessed the range of numbers from their phone book listing.
At last the modem emitted a squeal of static, the sound of two computers shaking hands.
The Doctor’s hands landed on the keyboard at a run. ‘I’m going to try a series of account names,’ he said, ‘typically left behind by programmers as back doors into the system for testing.’ He could type almost as fast as the modem could send data, so I was able to watch his attempts to break and enter as they piled up on the screen. Each time, he just hit ‘enter’
instead of typing a password:
Login: guest
Password:
Username or password incorrect; please
try again
Login: public
Password:
Username or password incorrect; please
try again
Login: sys
Password:
Username or password incorrect; please
try again
At last he sat back with a sharp sigh, and disconnected the modem. ‘It looks as though Swan has nailed shut the back doors into her system.’
‘So how are you going to get a real password?’ I said.
‘With a little luck, I still won’t need one. A friend of mine has set up a legitimate account for me. I can try to break into Swan’s computer again from there’
I watched as he logged in to the university’s computer as doctor. ‘Now,’ he said. ‘From here we use a program called telnet to jump to Swan’s computer.’
telnet tla2 25
After a few moments, the TLA computer responded with a ready message.3 The Doctor’s mouth lengthened into a smile.
‘You see?’ he said. ‘The computer’s not even asking us to log in. Port 25 is its email connection, and it has to be left open at all times: He was lecturing me, despite his earlier claim that he didn’t want to have to explain things. ‘Now, first we use the open port to send a message to ourselves.’
He typed rapidly, drumming his fingers on the pale plastic of the computer whenever he had to wait for the screen to catch up with him. Mail accepted, responded TLA’s computer. And sure enough, a short while later the email arrived at the Doctor account. The Doctor explained, ‘Now that the open port has seen us send a genuine email, it will 3 I have omitted the details of some of the Doctor’s methods to avoid encouraging would-be hackers – although this information is readily available if you know where to look.
assume anything else we do is also legitimate.’ I nodded, not wanting to interrupt the flow of his genius. ‘And that includes sending an email which will convince the TLA computer to open up a new account for us. One with all the privileges we need.’
He typed in a series of Unix commands, adding a special twist to the address of his ‘message’ so that the computer would be forced to execute those commands.
‘Now then,’ he said.
Login: jsmith
Password:
Ready tla2#
We were in. The Doctor looked like the cat that had got the cream. ‘Swan may be security-conscious,’ he said, ‘but even she hasn’t patched every puncture in her mainframe.’
Before he did anything else, the Doctor located the files which kept a record of the ports and logins, and snipped out the lines showing our unauthorised arrival. Then he spent a leisurely half an hour poking around in the guts of the TLA mainframe. Normally each user is locked into their own section of the computer, like residents in an apartment building, each with the key to their own door alone. The Doctor had convinced the computer to hand him the master key to the building, an account with root privileges, just as powerful as Swan’s own account. If he’d wanted to, he could have locked every user out of the computer, or have erased every file. A mistyped command