[ISN] MayDay! MayDay! Ruskies reinvent cyber crime

From: InfoSec News (alerts@private)
Date: Thu Feb 14 2008 - 09:33:19 PST


http://www.theregister.co.uk/2008/02/13/new_botnet_advances/

By Dan Goodin in San Francisco
13th February 2008

Researchers have unearthed two previously undetected botnets that 
exhibit sophisticated new capabilities that could significantly advance 
the dark art of cyber crime.

One of them, dubbed MayDay by security firm Damballa, uses new ways to 
send and receive instructions to infected machines. One communication 
method uses standard HTTP that is sent through an organization's web 
proxy. That allows the malware to circumvent a common security measure 
employed by many large companies.

Indeed, Tripp Cox, vice president of engineering and operations at 
Damballa, says he's observed MayDay running inside some of the world's 
most elite organizations, including Fortune 50 companies, educational 
institutions and ISPs. (He declines to identify them by name.)

"Most malware doesn't go through the trouble of trying to discover a 
computer's web proxy settings and use that as a method for getting onto 
the internet," he says.

The botnet also uses two separate peer-to-peer technologies so zombies 
can stay in touch with each other, presumably as a back-up measure in 
case the central channel is disconnected. One protocol communicates 
using the internet control message protocol (ICMP) and the other uses 
the transmission control protocol. The ICMP traffic is obfuscated so 
it's indecipherable to the human eye. Damballa researchers are still 
working to figure out exactly what kind of information is being 
transported over the channel.

Up until now, the zombie army popularly known as Storm has been the 
800-pound gorilla of the botnet underground. Having recently marked it's 
one-year birthday, it is believed to comprise about 85,000 infected 
machines. It was responsible for about 20 percent of the world's spam 
over the past six months, according to MessageLabs, which provides email 
and web filtering services to more than 16,000 business customers.

By comparison, MayDay and another newly discovered botnet called Mega-D 
have far fewer nodes, but they are worth watching for a couple reasons. 
For one, they are likely to get bigger over time. And for another, their 
increasing sophistication is a good indicator of the direction 
professional bot herders are headed.

MayDay has also done a good job of flying under the radar. Infected 
machines have a limited amount of time to connect to the command and 
control channel. If the time stamp is more than a few hours old, the 
server returns an error message, making it hard for white-hat 
researchers and rival bot masters to perform reconnaissance. And 
according Cox, the vast majority of the anti-virus products fail to 
detect at least some of the samples obtained by Damballa researchers. 
(Symantec and Sophos, in postings here and here, question Damballa on 
this issue.)

There's another reason why MayDay has managed to remain under cover 
until now: it is still relatively small. At any given time, there are 
only "several thousand victims" infected, according to Cox.


Tenacious D

The other recent arrival on the botnet scene is Mega-D. It was 
discovered by security firm Marshall, which last week said it had 
dethroned Storm as the top source of spam.

Some of Marshall's peers in the research community aren't so sure about 
that, including Joe Stewart of SecureWorks. He says Mega-D consists of 
about 35,000 bots, less than half the size of Storm. Mega-D isn't 
propagating as fast or efficiently is Storm has, either. Finally, he 
suspects spam from Storm is being under-counted.

Referring to Mega-D he says: "This is a very strong botnet, but hardly a 
challenger to Storm."

Nonetheless, Mega-D boasts some advances that Stewart says aren't common 
in botnets. One of them allows it to avoid being "greylisted," a 
technique used by email servers to prevent spam by instructing 
unrecognized senders to retransmit the email later. Whereas most spam 
bots give up, Mega-D bots don't.

"This is the first time I've seen any bot have any type of code in it 
dealing with greylisting," Stewart says. "This is actually at the bot 
level."

Stewart says Mega-D is the work of Russian hackers and has its genesis 
in a little-known family of malware known as "Ozkok." It is detected by 
most anti-virus products, but usually is only flagged with generic 
labels such as "Pakes" or "Agent," which may partly explain why Mega-D 
has been able to grow into such a large army with seemingly no one 
noticing.

While the newcomers aren't as big as Storm and, depending on who's 
asked, aren't believed to be as big of a nuisance, they are a reminder 
that the development of malware is a growing business that places a high 
value on innovation. MayDay's ability to communicate within heavily 
fortified businesses shouldn't be taken lightly. Neither is Mega-D's 
anti-greylisting capability.

In its first year, Storm showed a preternatural ability to stop on a 
dime, morph and take on new capabilities. Here's wondering how soon its 
developers adopt some of these latest bells and whistles?


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