Feeds

Dr. Web disputes Flashback Mac Trojan bot army estimates

Much bigger than Symantec says

The Power of One eBook: Top reasons to choose HP BladeSystem

Efforts by Apple and anti-virus vendors to kill the vast botnet assembled by notorious Flashback Mac Trojan may be much less successful than previously thought.

Symantec last week suggested the Mac botnet shrank from a peak of 670,000 to 140,000 following the release of clean-up tools.

But the Russian anti-virus firm Dr. Web says the figures are wrong because infected machines that contact a particular server freeze up and do not contact vendor-established sinkholes. These machines are not counted, even though they are still infected.

Dr. Web thinks 570,000 systems are still infected by the Flashback Trojan. Symantec concedes that Dr. Web has a point and in response has revised figures upwards, albeit to the more modest figure of 185,000.

"A recent Dr. Web blog post reveals our sinkholes are receiving limited infection counts for OSX.Flashback.K," Symantec explains in an updated advisory. "A sinkhole registered at IP address 74.207.249.7 is causing Flashback connections to hang as it never closes the TCP handshake, in effect preventing Flashback from hitting subsequent domains."

The Flashback Trojan created a zombie army of 650,000 Apple Macs, or more, by exploiting a Java security vulnerability that Apple patched is early April, some six weeks after a patch for Windows machines became available. Mac users only needed to visit an infected site to get hit - no user interaction was required.

The initial success of the worm has spawned a series of copy-cat attacks. Flashback-S. Mac security specialist Intego reports that Flashback-S cleans itself from the Java cache to avoid detection. Flashback-S spreads by taking advantage of the same Java vulnerability as the original Trojan.

Analysts from Kaspersky have traced the initial spread of Flashback from somewhere between 30,000 to 100,000 vulnerable WordPress blogs. It thinks a Russian cyber-criminal partner programme is behind the distribution of the malware.®

Designing a Defense for Mobile Applications

More from The Register

next story
Secure microkernel that uses maths to be 'bug free' goes open source
Hacker-repelling, drone-protecting code will soon be yours to tweak as you see fit
How long is too long to wait for a security fix?
Synology finally patches OpenSSL bugs in Trevor's NAS
Roll out the welcome mat to hackers and crackers
Security chap pens guide to bug bounty programs that won't fail like Yahoo!'s
HIDDEN packet sniffer spy tech in MILLIONS of iPhones, iPads – expert
Don't panic though – Apple's backdoor is not wide open to all, guru tells us
Researcher sat on critical IE bugs for THREE YEARS
VUPEN waited for Pwn2Own cash while IE's sandbox leaked
Four fake Google haxbots hit YOUR WEBSITE every day
Goog the perfect ruse to slip into SEO orfice
Putin: Crack Tor for me and I'll make you a MILLIONAIRE
Russian Interior Ministry offers big pile o' roubles for busting pro-privacy browser
prev story

Whitepapers

Designing a Defense for Mobile Applications
Learn about the various considerations for defending mobile applications - from the application architecture itself to the myriad testing technologies.
Implementing global e-invoicing with guaranteed legal certainty
Explaining the role local tax compliance plays in successful supply chain management and e-business and how leading global brands are addressing this.
Top 8 considerations to enable and simplify mobility
In this whitepaper learn how to successfully add mobile capabilities simply and cost effectively.
Seven Steps to Software Security
Seven practical steps you can begin to take today to secure your applications and prevent the damages a successful cyber-attack can cause.
Boost IT visibility and business value
How building a great service catalog relieves pressure points and demonstrates the value of IT service management.