Feeds

Blaster variant offers ‘fix’ for pox-ridden PCs

Do-gooder bug poses its own problems

  • alert
  • submit to reddit

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

A new variant of the infamous Blaster worm which claims to fix infected systems is circulating on the Net.

The Welchia worm exploit the same Remote Procedure Call (RPC) DCOM vulnerability used by Blaster to load itself onto unpatched Windows machines.

Welchia (AKA MSblast-D, Nachi and LovSan-D) also exploits the WebDav vulnerability (see this MS advisory from March) using TCP port 80. The worm specifically targets machines running Microsoft IIS 5.0 Web server.

Once it loads itself onto machines, Welchia attempts to download the DCOM RPC patch from Microsoft's Windows Update Web site, install it, and then reboot the computer. The worm also attempts to remove Blaster from infected systems.

Welchia checks for active machines to infect by sending an ICMP echo, or PING, which will result in increased ICMP traffic.

Despite an apparent lack of malicious intent, Welchia is still creating a great deal of unwanted traffic as it scans for new computers to infect. And the worm attempts to alter machines without their user's permission.

Welchia provokes the same ethical issues as CodeGreen, the virus-like code that attempted to patch systems infected with the Code Red worm. CodeGreen only spread itself onto servers that scan a box onto which it has been installed - so it is far less aggressive than Welchia.

The idea of "fighting fire with fire" in this way was used before by the Cheese worm, which fixed a flaw exploited by the Li0n worm on vulnerable Linux boxes.

Meanwhile, the original Blaster worm (and its variants) continue to spread. According to Network Associates' Hackerwatch.org operation, Blaster variants have infected more than 1.4 million PCs and continues to find fresh victims at a rate of between 15,000 to 35,000 per hour. After a marked decrease in the spread of the worm last Tuesday, rates of infection from Blaster variants have stayed consistently high. The data comes from information collected from users of McAfee's Personal Firewall application and does not distinguish between variants of the worm. ®

Related Stories

Blaster worm spreading rapidly
Blaster worm variants make mischief
Blaster rewrites Windows worm rules
Windows Update still standing despite Blaster
WindowsUpdate on Linux - an urban legend is born
Code Red busting code gets cool reception
'Friendly' Cheese worm reveals many compromised boxes

Designing a Defense for Mobile Applications

More from The Register

next story
DARPA-derived secure microkernel goes open source tomorrow
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
Don't look, Snowden: Security biz chases Tails with zero-day flaws alert
Exodus vows not to sell secrets of whistleblower's favorite OS
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
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.