http://www.computerworld.com/action/article.do?command=viewArticleBasic&taxonomyName=security&articleId=9013640 

By Jaikumar Vijayan
March 19, 2007 
Computerworld

The little lock icon that appears on a Web browser window frame when a 
secure connection exists between a browser and a Web server may be 
lulling users into a false sense of security.

The reality is that secure connections, in which data is encrypted using 
Secure Sockets Layer (SSL) technology before being transmitted over the 
Web, is increasingly being used to hide and spread malicious code, 
according to a report from security vendor Kaspersky Labs.

The issue is certainly not new. Security analysts have for long warned 
about the possibility of hackers exploiting encrypted SSL connections to 
sneak viruses and other malicious code past firewalls, antivirus 
software and intrusion detection systems. But what's lending greater 
urgency to the issue now is the widespread use of SSL communications by 
banks, retailers, e-commerce sites and e-mail providers on the Internet, 
said Shane Coursen, a senior technical consultant at Kaspersky.

"A lot of people, when they go to a Web site and see the picture of the 
lock on their browsers, assume the connection they have with the server 
is secure" and pay little attention to the data being exchanged, he 
said. All that a secure connection is designed to do is to verify the 
identity with whom information is being exchanged and then use 
encryption to protect the information from being viewed or modified by a 
third party.

There is usually little validation of the content being transmitted 
during such sessions. As a result, rogue hackers can use the connections 
as a way to transmit and spread malicious code, including Trojan horse 
programs and e-mail worms on client systems and Web servers, Coursen 
said.

"There are misconceptions that technologies such as SSL indicate that a 
Web site is safe when, in fact, it is not," said John Weinschenk, CEO 
and president of security firm Cenzic Inc. "A Secure Sockets Layer 
function certifies that the server the browser is talking to is the 
genuine site and provides encryption of data being transmitted."

While the technology does have a valid use and does provide some level 
of security, it still allows hackers to exploit underlying applications, 
he said. "While large companies have taken significant measures to 
secure their sites, the fact remains that there are holes hackers can 
exploit, and personal information can be compromised unless proactive 
measures are taken."

Traditional antivirus tools and intrusion detection systems are 
inadequate because they are not designed to detect malware in an 
encrypted connection. So malicious data within secure channels can cause 
a significant amount of damage, Coursen said.

But options are becoming available to deal with the issue, said Pete 
Lindstrom, an analyst with Midvale, Utah-based Burton Group. Vendors of 
intrusion detection systems, for instance, offer tools that can 
intercept an encrypted data stream, scanning the contents for malware 
and then passing it along to the destination in encrypted fashion, 
Lindstrom said.

According to the Kaspersky report, however, the problem with that 
approach is that the data stream is modified -- meaning the Web server 
cannot verify the authenticity of a client and a client cannot verify 
the authenticity of a server.

Most antivirus vendors today also offer Web application plug-ins that 
allow for the content in secure connections to be inspected, Coursen 
said. But some applications such as Microsoft Outlook and Outlook 
Express don't work very well with the plug-ins, he said.


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