Klez: Don't Believe 'From' Line
By Michelle Delio
2:00 a.m. April 30, 2002 PDT
Some Internet users have recently received an e-mail message from a dead friend.
Others have been subscribed to obscure mailing lists. Some have lost their
Internet access after being accused of spamming, and still others have received
e-mailed pornography from a priest.
They're actually experiencing some of the stranger side effects of the Klez
These ersatz e-mails containing the virus are creating Klez-provoked arguments
and accusations that are now spreading as fast as the worm itself.
The latest variant of the Klez virus started spreading 10 days ago. The virus
e-mails itself from infected machines using a bogus "From" address randomly
plucked from all e-mail addresses stored on an infected computer's hard drive or
Recipients of the virus-laden e-mails, not understanding that the "From"
information is virtually always phony -- or even that they have received a
virus -- have been clogging networks with angry and confused e-mails that are
causing a great deal of cyber-havoc.
People signing up for newsletters and mailing lists that they never subscribed
to has been a major source of frustration for both users and the list owners.
If Klez happens to send an e-mail "from" a user to an e-mail list's
subscribe address, the list software assumes the e-mail is a valid subscription
request and begins sending mail to the user.
A mailing list for fans of the Grammy Award-winning Steely Dan band has posted
an explanation directed to those who were subscribed to the list by the virus.
"We are not infected with the Klez virus. We don't know if you are infected with
the Klez virus. You may be. But even if you are not, someone out there who is
infected has both your address and our address on their computer ... and therein
lies the problem," the explanation reads, in part.
Even when users understand the source of newsletter-generated e-mails, the
amount of mail some lists generate is causing problems.
"Last week I suddenly started getting hundreds of e-mails, daily, with
information about raising tropical fish, purchasing cosmetics and staying in
youth hostels," Victor Montez, a sales rep for a publishing firm, said. "I do
not keep fish, wear makeup or travel rough."
Montez now understands the e-mails came from Klez-subscribed news lists. But he
said that since his free e-mail account only stores a certain amount of
messages, he's lost access to the account twice this week. He believes he's also
lost a significant amount of business-related e-mails.
"If this keeps up, I may end up having to stay in hostels and I'll have plenty
of free time to devote to raising fish," he said.
In some cases, it almost seems as if Klez is specifically targeting particularly
vulnerable e-mail addresses onto which it can piggyback.
E-mails containing an invitation to view what purports to be an attachment with
pornographic images appears at first glance to have been sent out by Catholic
parishes in New York and Maryland. The attachment actually contains the Klez
virus, and tracing information indicates the e-mails were actually sent from an
Internet service located in the United Arab Emirates.
"While we would obviously never choose to have our churches' names affiliated
with such material, this is a particularly difficult time to have e-mail with
obscene references -- which appear to have been sent by church staff --
circulating," an archdiocese spokeswoman said, referring to the worldwide sex
Other newsletter owners are also suffering. Some say their Internet service
providers have accused them of spamming non-members. Many ISPs cut service when
they receive a certain amount of spam complaints.
"I was reported to my ISP over a dozen times this week for spamming," said
Carlone, the manager of an e-mail newsletter for classic car enthusiasts. "My
ISP threatened to pull my account after the third complaint and we went down
shortly afterwards. It took four days to sort the problem out."
Andrew Fiber, maintainer of a Jewish folk music mailing list, said that the list
has been inundated with messages about widely off-topic subjects, so much so
that Fiber wondered if most of his members had suddenly gone "meshuga (a little
But then Fiber began getting the complaints.
"All of a sudden we had e-mails coming in from around the world, with people
yelling we had sent them Klez," Fiber said. "The thing is that 'Klezmer'
type of traditional folk music which we often discuss on the list and sometimes
refer to as Klez. So I thought people were protesting about our folk music. It
was very confusing for a while."
Some users have even reported receiving spooky e-mails from deceased friends.
"I belonged to a tattoo artists' list that closed down a few years ago. Last
week, I began getting e-mails from the list. Even weirder, I got eight e-mails
with subject lines that read 'SOS' and 'Eager to See You' from a list
died last year. It totally creeped me out," said "Bear" Montego.
Klez e-mails' subject lines are randomly chosen from a pre-programmed list of
about 120 possibilities, including "Let's be friends," "Japanese
pictures," "Meeting Notice," "Hi Honey" and "SOS."
Klez also sends fake "returned" or "undeliverable" e-mails, advising
supposed sender that their original, refused e-mail is contained in the
attachment. Clicking on the attachment triggers the virus.
The virus can launch automatically when users click to preview or read e-mails
bearing Klez on systems that have not been patched for a year-old vulnerability
in Internet Explorer, Outlook and Outlook Express. Klez only affects PCs running
Microsoft's Windows operating system.
As of Monday afternoon, Klez's spread seems to have slowed, but antiviral
experts warn that the worm will be around for a while.
"Anytime you have a virus that is not easily identifiable visually, it tends to
linger," Rod Fewster, Australian representative for antiviral application NOD32,
said. "SirCam and Klez both vary the subject lines of the e-mails they send,
which makes it hard for the average user to spot."