Feeds

Thousands of WordPress sites commandeered by Black Hole

Webmasters, update TimThumb now!

Providing a secure and efficient Helpdesk

Mass attacks that exploit a known vulnerability in the WordPress publishing platform have continued to bear fruit for hackers, with thousands of websites claimed in the past few weeks, a researcher said.

The security bug, in a widely used image resizing utility known as TimThumb, allows attackers to seize control of WordPress websites, one of the victims warned nine weeks ago. A few days later, a security researcher found almost 4,400 WordPress sites had been commandeered in an attack that poisoned Google Image results with sites that attempted to trick users into installing counterfeit antivirus software. He speculated the cause was the same TimThumb exploit.

Although a fix for the TimThumb vulnerability has been available for more than two months, plenty of websites remain vulnerable. According to a research report published by Avast on Monday, thousands of websites have been infected by Black Hole, a hack-by-numbers toolkit available in underground forums for about $1,500 or for free for a scaled-down version. The kit installs an iframe in infected sites that silently redirects visitors to malicious sites.

"The bad guys are using a security vulnerability in non-updated TimThumb," Avast researcher Jan Sirmer wrote. "This allows attackers to upload and execute arbitrary PHP code in the TimThumb cache directory which will download other malicious files."

Avast alone blocked the redirection attempts from 3,500 unique websites in August and 2,515 sites last month, and Sirmer said he expects to see similar results this month. That may be only a small percentage of the total number of infected sites, since Avast is used by a small minority of people browsing the web. Sirmer said attackers may have compromised some of the websites by exploiting weak passwords.

Once a site is infected, it's not always easy to remove all the malicious code. Denis Sinegubko, the Russian researcher who discovered the WordPress attack used to poison Google Image results, has advised webmasters of compromised sites to look for rogue rules in the .htaccess files in the site root and above the site root directory. He has more here. ®

Choosing a cloud hosting partner with confidence

More from The Register

next story
SMASH the Bash bug! Apple and Red Hat scramble for patch batches
'Applying multiple security updates is extremely difficult'
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
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.