By Jaikumar Vijayan
March 19, 2007
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
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
"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,
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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