Three French journalists have been booted for life from Black Hat and Defcon for compromising the Black Hat press room wired network and grabbing the credentials for at least one reporter. Their goal was to publicize the risks to reporters especially current given the massive reporter presence in Bejing for the Olympics. This risk is certainly real and it is a shame that these journalists had to compromise and embarass one of their own and potentially run afoul of US Federal wiretap laws.
Sniffing, or monitoring all traffic on a network, is so 1999. That is when L0pht came out with AntiSniff, which could detect many scenarios where someone was sniffing a wired network. How can we be using plain text authentication protocols in 2008? It is a well known and easily solved problem. But people authenticate in clear text everyday when they log into social networking or blogs or other "unimportant" applications. The problem is when they use those same credentials for work or online banking. We need to think of any application that alows users to authenticate in the clear as broken. If 3 journalists can monitor passwords, anyone can.
Update 08/08/2008 12:30pm EST:
It turns out the attack was likely a MITM attack where the attackers ran their own DHCP server and handed out a gateway IP that was controlled by them. At least one reporter was connecting to his organization's content management system over unencrypted HTTP and got his password compromised. More details in "How eWeek Got Hacked at Black Hat."