, SecurityFocus 2001-02-26
ShareSniffer turns Windows hacking into a P2P play.
When you enter through an open file share, that's likely an unauthorized access.
ShareSniffer Inc.'s newly-launched software, also called
Microsoft Windows' NetBIOS support makes it easy to share hard drives and printers over a network. But users who configure their home or office network for file sharing often inadvertently make their files accessible from the Internet as well. If such a user hasn't chosen a file sharing password, then their disk drives are open to anyone who knows their system's Internet (IP) address.
These so-called "open shares" are one of the Internet's most persistent security issues. The problem made the SANS Institute's list of top ten security holes in 2000, and has been the subject of warnings from the government-funded Computer Emergency Response Team (CERT), and the FBI's National Infrastructure Protection Center (NIPC). The vulnerability is a favorite among computer intruders and virus writers: last year even saw a malicious worm that spread through open shares, seized victims' modems and dialed 911.
ShareSniffer Inc. appears to be the first enterprise to try to harvest open shares for commercial gain. The three-person company offers the software as a free download, but plans to offer more full-featured versions for between $5 and $100.
A program that scans Internet addresses for unprotected disk drives might be viewed as a hacking tool. But to the man who wrote it, ShareSniffer is an honest peer-to-peer venture that brings out the full potential of Windows' networking features.
"I want people to know that they don't have to take the time to make a web site and pay somebody to host it," says ShareSniffer Inc. co-founder Kerry Rogers, 40, the author of the program. "All they have to do is right-click on a folder, and they can make all their music and art and other incredible stuff available to the world."
Others see it differently. "Federal law makes it illegal to knowingly obtain unauthorized access to a computer," says Mark Rasch, a former federal computer crime prosecutor, now an attorney with the Science Applications International Corporation (SAIC).
"The person who has, through no knowledge of his own, left file sharing 'on' with no protection, that is the electronic equivalent of leaving your door unlocked," says Rasch. "You can't with any degree of certainly say it is an invitation to enter... Therefore when you enter through an open file share, that's likely an unauthorized access."
"We have a bevy of lawyers that say just the opposite," Rogers claims. Rogers also points out that ShareSniffer only locates open shares, it doesn't access them. The user does that through normal Windows functionality.
Programs that scan for open shares are already available online -- as hacking and security auditing tools. What distinguishes ShareSniffer is the user interface, which has all the trappings, icons and trademark touches you'd expect from a serious P2P commercial software package. A user selects a block of Internet addresses and clicks on an icon to set the program's scanning engines, or "nostrils," into action. ShareSniffer eventually returns a list of addresses with open shares.
The program automatically posts its bounty of unprotected systems to a particular Usenet news group, where other ShareSniffer clients can pick it up and display it. "It's distributed computing -- everyone is getting the benefits of everyone else's sniffing," explains Rogers. As a side effect, the ShareSniffer news group has quickly become an open repository of unprotected systems. Monday morning, thirty Internet addresses were listed.
In a Usenet posting, Rogers predicted that number will "soon easily exceed 2000 per day," and will increase ten-fold in the months to come.
Rogers maintains that those open shares are not accidents or security holes: people share files deliberately, he says, particularly on college campuses, where students use open shares to swap music and software with one another. "I want to emphasize that this is public and voluntary," says Rogers. "Microsoft Windows by default will not expose files to the Internet. It has to be consciously configured to expose files to the Internet."
But Patrick Prokop, a T.V. weatherman in Savannah, Georgia, says he never intended to open his home computer to the world. Nevertheless, a ShareSniffer client sniffed out Prokop's machine earlier this month, apparently in pre-launch testing by the company, and the address was posted on Usenet. On Friday, anyone could read, modify, or delete files on Prokop's system.
"I don't like that idea," said Prokop, after SecurityFocus notified him that his computer was accessible. Prokop says he meant to share files between two computers on a home network, and didn't realize they were accessible to everyone else. "I'll have to password protect them, or put a firewall up."
Asked about Prokop's system, Rogers acknowledged that ShareSniffer may expose unintentional file shares. "We're seeing stuff on the Usenet group that we don't necessarily want to see," he admits, but he claims that will become rare when ShareSniffer catches on. "People will realize that they're going to be exposed."