Embedded HTML 'bugs' pose potential security risk

[InfoSec News <isn () C4I ORG>]

http://www.infoworld.com/articles/hn/xml/00/12/05/001205hnwebbug.xml?p=br&s=2

By Heather Harreld
Tuesday, Dec. 5, 2000 3:01 pm PT

ALTHOUGH SEASONED NETWORK administrators may have grown accustomed to
the nuisance of unsolicited e-mail, or spam, these messages may soon
pose severe security threats to company networks, thanks to emerging
software geared to give e-marketers more access to personal data.

Marketing companies have begun to embed invisible HTML "bugs" or
"beacons" in their e-mail. Because these tiny one-pixel images must be
retrieved from the sender's server when the message is opened, they
can tell the sender when and how often a recipient looks at a message.
HTML makes browsers launch and the senders can place cookies on every
PC that accepts the e-mail message with a bug. As a result, those
cookies allow the sender to gather information like the recipient's IP
address, the type of browser they use and the Web sites they visit,
according to experts.

While the tracking software may be a boon for the senders because they
can gauge the effectiveness of online ad campaigns -- perhaps using it
to know exactly when to call a recipient at their desk -- it could
also be exploited to transmit viruses or as a tool for spammers to
gain hundreds of corporate e-mail addresses, industry experts warn.

"It's just a matter of time [before] someone [can] figure out how to
use these things against people or corporations," said Sharon Ward,
director of enterprise business applications at Hurwitz Group, in
Framingham, Mass.

Ward said that because the software requires a query to the sender's
server, these bugs could be used to send e-mail viruses. "It could be
a tricky little Trojan Horse for getting viruses into unsuspecting
people's e-mail. You just open up this message ... and it could send
them off to everyone in your address book. You sort of think that if
you're going to get an e-mail virus ... it's not going to come from a
company trying to sell you a product."

Only two or three companies have developed this type of tracking
software with a couple hundred marketers using it, Ward said.

In addition, spammers could use the bugs to get additional information
about a company's e-mail addresses, said John Mozena, co-founder of
the Coalition Against Unsolicited Commercial E-mail. Now, spammers can
only guess that their e-mail has reached a person if it doesn't bounce
back to them, he said. But because the Web bugs can confirm that the
e-mail has actually been opened, spammers would know how a corporation
builds e-mail addresses. They could then use software tools to
automatically compile a list of common names in the template the
company uses to devise e-mail addresses and lob more spam toward the
company, possibly clogging mail servers, Mozena said.

"Because of the HTML bugs, you've confirmed to the sender that you've
got the e-mail," Mozena said. "You've just made your address more
valuable. It makes it more likely that your address will be sold or
traded."

To help ward off the potential security pitfalls associated with the
bugs, administrators should ensure security settings on the desktop
are set so computers cannot run any unapproved script macros, Mozena
said.

In addition, there are companies that specialize in blocking spam from
entering the confines of a company's network. Brightmail offers a
server-side solution that is designed to filter spam before it reaches
mailboxes. Typically 30 percent of all corporate e-mail is spam,
according to Ken Schneider, CTO at San Francisco-based Brightmail.
While network administrators may seek to stem some of the problem by
blocking cookies in the browser, if the mail package is programmed to
accept cookies, then bugs could get to the user, he said.

Because the bugs allow marketers to confirm the validity of an e-mail
address, they also may pose privacy concerns. Very few of the
companies that use Web bugs detail how they use the software in their
privacy polices, said Richard Smith, co-founder of The Privacy
Foundation, in Washington. In addition to bugging e-mail, the software
can also be used to track which sites a user visits on the Internet
and to transmit information about a user, such as a zip code, from one
Web site to another, he added.

"It just says flat out that we're being tracked on the Internet," he
said.

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