At least 282,000 web pages have been hit by the latest SQL injection attack on web servers, according to Panda Security. And the number of seemingly legitimate web pages affected is growing.
Ryan Sherstobitoff, chief corporate evangelist at Panda Security, claimed that the attack's effect is well understood. Hackers inject SQL code in web pages by taking advantage of a vulnerability in Microsoft's Internet Information Services (IIS) web server.
“When someone clicks on a compromised page, the attack checks for five different [Microsoft] vulnerabilities on the user's PC, and if it finds one, redirects them to a malicious website that can install identity-stealing malware,” Sherstobitoff told SCMagazineUS.com Friday. The pages typically do not show any signs of being compromised, he added.
But Patrik Runald, security response manager at Finnish anti-virus firm F-Secure, the attack does not use vulnerabilities in IIS; rather, it is focused on exploiting ways to inject malicious code onto served pages.
“We looked at the IIS logs of the exploited sites, and it appears that the problem comes from servers that have not properly sanitized their code,” he told SCMagazineUS.com.
To alleviate the problem, administrators should make sure that all server patches are up to date and that servers are hardened, Runald said.
“It's important to filter for the malicious code,” he said.