, SecurityFocus 2002-06-24
The ex-hacker details his past control of Las Vegas' telecom network, and raids his old storage locker to produce the evidence.
Mitnick returned to the hearing room clutching a crumpled, dog-eared and torn sheet of paper.
The Sprint subsidiary lost that innocence Monday when convicted hacker Kevin Mitnick shook up a hearing on the call-tampering allegations by detailing years of his own illicit control of the company's Las Vegas switching systems, and the workings of a computerized testing system that he says allows silent monitoring of any phone line served by the incumbent telco.
"I had access to most, if not all, of the switches in Las Vegas," testified Mitnick, at a hearing of Nevada's Public Utilities Commission (PUC). "I had the same privileges as a Northern Telecom technician."
Mitnick's testimony played out like a surreal Lewis Carroll version of a hacker trial -- with Mitnick calmly and methodically explaining under oath how he illegally cracked Sprint of Nevada's network, while the attorney for the victim company attacked his testimony, effectively accusing the ex-hacker of being innocent.
The plaintiff in the case, Munoz, 43, is accusing Sprint of negligence in allegedly allowing hackers to control their network to the benefit of a few crooked businesses. Munoz is the publisher of an adult advertising paper that sells the services of a bevy of in-room entertainers, whose phone numbers are supposed to ring to Munoz's switchboard. Instead, callers frequently get false busy signals, or reach silence, Munoz claims. Occasionally calls appear to be rerouted directly to a competitor. Munoz's complaints have been echoed by other outcall service operators, bail bondsmen and private investigators -- some of whom appeared at two days of hearings in
Munoz hired Mitnick as a technical consultant in his case last year, after SecurityFocus Online
Mitnick admitted that his testing produced no evidence that Munoz is experiencing call diversion or blocking. But his testimony casts doubt on Sprint's contention that such tampering is unlikely, or impossible. With the five year statute of limitations long expired, Mitnick appeared comfortable describing with great specificity how he first gained access to Sprint's systems while living in Las Vegas in late 1992 or early 1993, and then maintained that access while a fugitive.
Mitnick testified that he could connect to the control consoles -- quaintly called "visual display units" -- on each of Vegas' DMS-100 switching systems through dial-up modems intended to allow the switches to be serviced remotely by the company that makes them, Ontario-based Northern Telecom, renamed in 1999 to Nortel Networks.
Each switch had a secret phone number, and a default username and password, he said. He obtained the phone numbers and passwords from Sprint employees by posing as a Nortel technician, and used the same ploy every time he needed to use the dial-ups, which were inaccessible by default.
With access to the switches, Mitnick could establish, change, redirect or disconnect phone lines at will, he said.
That's a far cry from the unassailable system portrayed at the March hearings, when former company security investigator Larry Hill -- who retired from Sprint in 2000 -- testified "to my knowledge there's no way that a computer hacker could get into our systems." Similarly, a May 2001 filing by Scott Collins of Sprint's regulatory affairs department said that to the company's knowledge Sprint's network had "never been penetrated or compromised by so-called computer hackers."
Under cross examination Monday by PUC staff attorney Louise Uttinger, Collins admitted that Sprint maintains dial-up modems to allow Nortel remote access to their switches, but insisted that Sprint had improved security on those lines since 1995, even without knowing they'd been compromised before.
But Mitnick had more than just switches up his sleeve Monday.
The ex-hacker also discussed a testing system called CALRS (pronounced "callers"), the Centralized Automated Loop Reporting System. Mitnick first described CALRS to SecurityFocus Online last year as a system that allows Las Vegas phone company workers to run tests on customer lines from a central location. It consists of a handful of client computers, and remote servers attached to each of Sprint's DMS-100 switches.
Mitnick testified Monday that the remote servers were accessible through 300 baud dial-up modems, guarded by a technique only slightly more secure than simple password protection: the server required the client -- normally a computer program -- to give the proper response to any of 100 randomly chosen challenges. The ex-hacker said he was able to learn the Las Vegas dial-up numbers by conning Sprint workers, and he obtained the "seed list" of challenges and responses by using his social engineering skills on Nortel, which manufactures and sells the system.
The system allows users to silently monitor phone lines, or originate calls on other people's lines, Mitnick said.
Mitnick's claims seemed to inspire skepticism in the PUC's technical advisor, who asked the ex-hacker, shortly before the hearing was to break for lunch, if he could prove that he had cracked Sprint's network. Mitnick said he would try.
Two hours later, Mitnick returned to the hearing room clutching a crumpled, dog-eared and torn sheet of paper, and a small stack of copies for the commissioner, lawyers, and staff.
At the top of the paper was printed "3703-03 Remote Access Password List." A column listed 100 "seeds", numbered "00" through "99," corresponding to a column of four digit hexadecimal "passwords," like "d4d5" and "1554."
Commissioner Escobar Chanos accepted the list as an exhibit over the objections of Sprint attorney Patrick Riley, who complained that it hadn't been provided to the company in discovery. Mitnick retook the stand and explained that he used the lunch break to visit a nearby storage locker that he'd rented on a long-term basis years ago, before his arrest. "I wasn't sure if I had it in that storage locker," said Mitnick. "I hadn't been there in seven years."
"If the system is still in place, and they haven't changed the seed list, you could use this to get access to CALRS," Mitnick testified. "The system would allow you to wiretap a line, or seize dial tone."
Mitnick's return to the hearing room with the list generated a flurry of activity at Sprint's table; Ann Pongracz, the company's general counsel, and another Sprint employee strode quickly from the room -- Pongracz already dialing on a cell phone while she walked. Riley continued his cross examination of Mitnick, suggesting, again, that the ex-hacker may have made the whole thing up. "The only way I know that this is a Nortel document is to take you at your word, correct?," asked Riley. "How do we know that you're not social engineering us now?"
Mitnick suggested calmly that Sprint try the list out, or check it with Nortel. Nortel could not be reached for comment after hours Monday.
The PUC hearing is expected to run through Tuesday.