Roger A. Grimes:

For the past few months an acquaintance of mine has been sniffing various public wireless and wired networks around the world, looking to see what plain text passwords are visible. It was an eye-opening experiment.

She used a bunch of different tools, but mostly Cain. At the moment, it collects 18 different passwords or password representations, including plain text passwords sent over HTTP, FTP, ICQ, and SIP protocols, and will automatically collect the user’s log-in name, password (or password representation), and access location.

Other than a few simple validity reviews and summary counts, my friend doesn’t look at the log-in names or passwords, and she deletes any collected information after obtaining the counts. She hasn’t used ARP (Address Resolution Protocol) poisoning or done anything other than to count plain text passwords passing by her traveling laptop’s NIC when she’s in a hotel, airport, or other public network.

Although some — including me — might question her ethics, the information she shared is useful in understanding our true state of insecurity.

She said about half the hotels use shared network media (i.e., a hub versus an Ethernet switch), so any plain text password you transmit is sniffable by any like-minded person in the hotel. Most wireless access points are shared media as well; even networks requiring a WEP key often allow the common users to sniff each other’s passwords.

She said the average number of passwords collected in an overnight hotel stay was 118, if you throw out the 50 percent of connections that used an Ethernet switch and did not broadcast passwords.

The vast majority, 41 percent, were HTTP-based passwords, followed by e-mail (SMTP, POP2, IMAP) at 40 percent. The last 19 percent were composed of FTP, ICQ, SNMP, SIP, Telnet, and a few other types.

As a security professional, my friend often attends security conferences and teaches security classes. She noted that the number of passwords she collected in these venues was higher on average than in non-security locations. The very people who are supposed to know more about security than anyone appeared to have a higher-than-normal level of remote access back to their companies, but weren’t using any type of password protection.

More here.