Feeds

Blaster variant offers ‘fix’ for pox-ridden PCs

Do-gooder bug poses its own problems

  • alert
  • submit to reddit

Providing a secure and efficient Helpdesk

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

Choosing a cloud hosting partner with confidence

More from The Register

next story
Shellshock: 'Larger scale attack' on its way, warn securo-bods
Not just web servers under threat - though TENS of THOUSANDS have been hit
Apple's new iPhone 6 vulnerable to last year's TouchID fingerprint hack
But unsophisticated thieves need not attempt this trick
PEAK IPV4? Global IPv6 traffic is growing, DDoS dying, says Akamai
First time the cache network has seen drop in use of 32-bit-wide IP addresses
Oracle SHELLSHOCKER - data titan lists unpatchables
Database kingpin lists 32 products that can't be patched (yet) as GNU fixes second vuln
Who.is does the Harlem Shake
Blame it on LOLing XSS terroristas
Researchers tell black hats: 'YOU'RE SOOO PREDICTABLE'
Want to register that domain? We're way ahead of you.
Stunned by Shellshock Bash bug? Patch all you can – or be punished
UK data watchdog rolls up its sleeves, polishes truncheon
prev story

Whitepapers

A strategic approach to identity relationship management
ForgeRock commissioned Forrester to evaluate companies’ IAM practices and requirements when it comes to customer-facing scenarios versus employee-facing ones.
Storage capacity and performance optimization at Mizuno USA
Mizuno USA turn to Tegile storage technology to solve both their SAN and backup issues.
High Performance for All
While HPC is not new, it has traditionally been seen as a specialist area – is it now geared up to meet more mainstream requirements?
Beginner's guide to SSL certificates
De-mystify the technology involved and give you the information you need to make the best decision when considering your online security options.
Security for virtualized datacentres
Legacy security solutions are inefficient due to the architectural differences between physical and virtual environments.