Conficker zombie botnet drops to 3.5 million
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The "activation" of Windows machines infected with the latest variant of the Conficker worm has allowed security watchers to come up with a far more accurate estimate of how many machines are infected.
Early versions of Conficker called home to 250 different domain names every day to check for updates. Since Wednesday, machines infected by with the latest version of the worm (Conficker-C) began using a sample of 500 out of pre-programmed 50,000 domains a day to search for upgrades.
The unknown virus writers who created the worm are yet to publish any such update, but the call-back behaviour has allowed anti-virus firms to come up with an estimate of how many machines are infected by Conficker-C for the first time.
Vietnamese antivirus firm Bkis reckons 1.3m machines are infected with Conficker-C. A breakdown of infections by country, compiled by Bkis, can be found here. The combined number of computers infected by Conficker A and B is 2.2m, according to Bkis.
That total of around 3.5m is in line with a detailed technical analysis by Conficker which puts the size of the Conficker botnet at between three and four million strong.
IBM's X-Force has a mash-up using Google Maps or Conficker infections across the world, which can be found here. The Conficker Working Group has published more detailed infection maps here.
Estimates of the number of machines ever infected by Conficker vary from ten to 15 million, but these figures ignored disinfections and other factors. It's more meaningful to talk of the current number of zombie drones rather than the number ever infected, because it gives a much better idea of the potential for harm.
As predicted by security watchers beforehand, Conficker's 1 April "activation" passed by without anything happening, much like previous malware trigger dates associated with nuisances such as the Michelangelo virus (1992), CIH (1999), SoBig (2003), and MyDoom (2004). The unknown authors of Conficker didn't publish updates on 1 April, but since infected machines check for updates on a daily basis it would be wrong to think that the threat has passed. Updates using the P2P mechanism built into the worm are also possible.
F-Secure has compiled an updated, informative FAQ on Conficker here, which cover important questions such as how to tell if you're infected and much more besides. Conficker blocks access to security sites, a factor exploited by Joe Stewart of the Conficker Working Group to create a simple test here. ®
COMMENTS
What the hell are those Confickers up to anyway?
I wish they'd pull the pin already.
I mean FFS, all the 'doze admins here need to be woken up every now and then and I've been patiently waiting for Conficker to be switched on. So far nothing but boring stories guestimating the size of the botnet.
Yawn.
Conficker?
I'll eat when I get hungry
I'll drink when I get dry
If the life I live don't kill me
Then I guess I'll never die
I'll tune up my fiddle
I'll rosin up my bow
And find a girl to hold me tight
Anywhere I go
Corn liquor corn liquor's what I cry
If you don't give me corn liquor boy
Somebody's gonna die
Somebody's gonna die oh lord
Somebody's gonna die
How about...
How about this for a revolutionary idea...
As this analysis is based on the IPs of the infected machines, how about emailing the ISPs who control these IPs and asking them to inform the user who had that IP allocated at the time of their infection, and pass them some useful links to help them remove the infection...
The mechanism almost already exists on some ISPs to allow the RIAA to pump out the automated "You are an evil pirate, prepare to be cut off!" emails.
This does assume the ISPs give a sh*t of course!

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