subject: Imperfect Storm aids spammers posted: Sun, 18 Feb 2007 00:05:20 -0000
[The best defence against this stuff is a spam filter, preferably one
where you can add custom regular expressions, and block all
executable attachments, as described here:
http://www.cyberdelix.net/tech/filtering.htm - Stu]
Imperfect Storm aids spammers
Robert Lemos, SecurityFocus 2007-02-16
For 24 hours in mid-January, stock-fraud investigation site
StockPatrol disappeared from the Internet, overwhelmed by a massive
flood of Web requests coming from thousands of sources.
The attack came after the site wrote a handful of reports
investigating and condemning the practice of pump-and-dump stock spam
campaigns. No fewer than three bot nets targeted StockPatrol as well
as another anti-spam site and at least five command-and-control
servers associated with a different virus, Warezov, according to an
analysis released last week.
"StockPatrol.com was the victim of a cyberspace assault that
evidently was calculated to disable our site and make our reports
inaccessible," read a statement posted on January 17. "In this
instance the attack was massive."
At the heart of the attack was a single program designed specifically
to co-opt victims' computers to aid in sending stock-touting e-mail
messages and to participate in denial-of-service attacks--Storm Worm.
The program appeared on January 19 and compromised systems by luring
their users into opening the attachments of messages with subject
lines regarding current news events--including violent storms in
Europe. Because the program does not propagate on its own, the name
adopted from its subject lines is a misnomer--the Storm Worm is
actually a Trojan horse.
The program highlights a number of changes in the techniques used by
criminal Internet groups. The Storm Worm spreads in fairly large, but
controlled, bursts of e-mail through previously compromised
computers. Each burst typically sends out a custom variant, causing
headaches for antivirus makers. (More on this in part two of this
series.)
"The outbreak occurred in smaller waves, much in the same way the
Warezov virus appeared," said Paul Wood, senior analyst with
MessageLabs. "Each of the waves appears with a dozen different
variants of the virus. They don't just carry on and on. They are
spammed out, then they wait a bit because the antivirus companies
create signatures, and then they spam out a new set of variants."
At one point, the creators of the Storm program sent out a new set of
variants daily, forcing antivirus firms into a running battle to
protect their users.
"Every day, it has been a new set of subject lines and new tactics to
get people to open these," Allysa Myers, virus research engineer for
security software maker McAfee, said in late January. "They have had
mass seedings of new variants every day this week."
Highlighting another trend, bot nets created with the program use
peer-to-peer communication to make shutting down the illicit networks
much more difficult. Typically, bot nets last no more than a day
after their command-and-control server is identified. The peer-to-
peer component of the Storm Worm enables its bot nets to reconstitute
themselves after the central server is taken down.
"In the traditional bot net, if you cut off the head, you kill the
beast," said Dean Turner, senior manager of development for security
firm Symantec, the owner of SecurityFocus. "We speculate that, as
more command-and control servers get identified by ISPs, you will see
more and more of these bot nets go to peer-to-peer."
For all that, the techniques are not new, said Joe Stewart, senior
security researcher with SecureWorks. Stewart penned last week's
analysis connecting Storm Worm to the denial-of-service attacks.
"I don't think Storm is any large step forward," Stewart said.
"Everything it does, we have seen in one form or another before.
Someone has sat down and decided what they wanted and built it out of
technology that is already out there."
Attacks on rival spam gangs and anti-spam sites are not that unique
either. Yet, the people who are propagating the Storm Worm have not
been shy about the attacks, Stewart said. Attacks were also leveled
at anti-spam site SpamNation, which maintains a list of the latest
stock touts, and money transfer site CapitalCollect.
"The spam war is escalating to new levels," wrote Stewart in an
analysis posted on SecureWorks' blog. In the analysis, he pointed to
the successful attack on anti-spam firm Blue Security as possibly
emboldening the spammers. That company folded after the May 2006
assault.
"With no repercussions from that attack, or even older attacks which
shut down certain DNS blacklists, it seems that more spammers are
willing and able to attack anyone who threatens their profit
potential," he said.
That includes rivals. The Storm Worm bot nets attacked five Web sites
associated with a competing program, Warezov. The reason is clear,
said SpamNation's anonymous editor: Spammers that are about to pump
up one stock don't want their competitor blunting the effect or
confuse the potential marks by pumping a different stock.
"It shouldn't come as any surprise to learn that spammers are
fighting amongst themselves," the editor wrote in a recent post. "The
fiercest competitors of any organism are other members of its own
species, which compete for the same food and resources that it needs
to survive and breed."
Warfare among malware writers is standard fare. The author of
variants of the Netsky virus often taunted the writers of MyDoom and
Bagle. In 2005, the groups behind different variants of the Zotob
virus attempted to attack and control the machines compromised by
their competitors.
In this case, the battle between the two groups pits gangs of two
nationalities against each other, according to SecureWorks' Stewart.
All signs indicate that Warezov is used by attackers based in China,
Stewart said. Bot nets created with the Trojan horse program take
commands from servers in China and the code uses the MEW packer, a
compression utility favored by the Chinese because it has releases in
Mandarin.
The Storm Worm on the other hand uses packers favored by Russian
groups and has connections to servers based in Russia, he said.
While the attacks have moved beyond a war of egos, they remain bold
just the same. And without much luck in hunting down the people
behind the bot nets, it may not get better, Stewart said.
"It seems like they feel they're in a position where they are
untouchable," he said.
