@Home's mis-configured proxy Excites hacker

A single misconfigured server exposed broadband provider Excite@Home's internal corporate network to hackers for at least three months, making its customer list of 2.95 million cable modem subscribers accessible to anyone with a Web browser and a modicum of cyber smarts, SecurityFocus has learned.

An Excite@Home spokesperson confirmed that the company recently shut down a rogue proxy server that had been running at its Redwood City, California headquarters. By configuring a Web browser to channel traffic through that proxy server, an outsider could surf the company's internal Web-based applications as an employee.

"It wasn't anything resembling rocket science," said Adrian Lamo, the hacker who discovered the hole, and reported it to Excite@Home last month. At twenty years-old, Lamo has carved out a niche exposing the security foibles of corporate behemoths, usually the Virginia-based America Online. Last year he helped expose a bug that was allowing hackers to hijack AOL Instant Messenger (AIM) accounts.

In January of this year, Lamo turned his attention to Excite@Home. He says he found the company's backbone network -- which serves cable modem subscribers throughout North America -- to be relatively secure. But the corporate network was another story. Wielding a common hacker tool called "Proxy Hunter," Lamo scanned the company's address space, and quickly discovered an open proxy running on a computer named "buddylee".

With buddylee's help, Lamo was able to hit a number of Web-based resources on the internal network, including the official Excite@Home employee directory, where he added his own name, "repeatedly," he says... just for fun.

More seriously, Lamo discovered a customer support Web site designed to be used by Excite@Home's cable company resellers, AT&T, Cox Cable, Century Communications, and dozens of others. He cracked it with a password he found posted on another internal Web site, and gained access to a database of names, email addresses, billing addresses, cable modem serial numbers, current IP addresses, computer operating system, and other technical information on all of the company's broadband subscribers. The company boasted 2.95 million customers as of November of last year.

"I was able to bring up the name of every Kennedy who subscribes, for example," said Lamo, who showed a sample of the data to SecurityFocus.

The company could not confirm that Lamo's access included all subscribers, but acknowledged that customer data was compromised. Company spokesperson Londonne Corder emphasized that no credit card data was involved, and that the proxy has since been taken down.

Widespread, overlooked

The incident highlights the danger that a single hole in a network's perimeter can pose. According to a member of Excite@Home's technical staff familiar with the incident, the proxy was set up automatically during a default install of a network management tool. But even after the system was shut down, other holes appeared. "We have 3,000 employees," says the staff member. "There have been other machines popping up with proxy servers on them."

The proxies are a weakness because they allow outsiders to masquerade as insiders, and Exite@Home's internal Web sites are programmed to trust surfers coming from company Internet addresses. "It's fairly widespread and poorly considered," says Lamo.

Computer security engineer Brian Martin of Maryland-based Digital Systems International Corporation says he hasn't seen proxies used to that effect before, but that in the abstract, the hole fits a timeworn pattern. "Misconfiguration, or not thinking of security as you set something up, in general that is very common," says Martin. "You see that every day."

Lamo said he continues to enjoy some level of access to the company network, and provided a convoluted Excite@Home URL that serves up access to the corporate directory, though Lamo's name no longer appears.

The company, meanwhile, seems grateful to the hacker. "He has demonstrated a certain amount of restraint, which we appreciate," says the technical staff member. "He hasn't done damage, we can't claim any sort of loss, and I don't believe we're interested in that."

Lamo brought the hole to the company's attention in late April, after skating around Excite@Home's internal web undetected for months. Following a late-night meeting at the company's headquarters, Lamo and corporate computer security experts converged on buddyholly -- which turned out to be a workstation on an employee's desk. While the security pros watched, Lamo closed the hole by cutting-off the offending machine from the Internet -- literally, using a pocket knife.

Today Lamo retains two trophies from the hack: the severed plug from buddylee's network cable, and an entry from the customer support database. The latter, by appearance, is the service record for Washington-state science fiction author Neal Stephenson, whose novels "Snowcrash" and "Cryptonomicon" grace many a hacker's bookshelf.

Lamo notes that Stephenson (or his namesake) reported his operating system as "CPM" -- an ancient operating system from the days of eight-bit microprocessors. It's an obscure joke that would likely be lost on a customer support representative, but draws an appreciative chuckle from the hacker.

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