The latest wave of attacks began on Friday morning and, at that time, 1,000 pages, including the websites for Chicago Public Radio and IndustryWeek, were infected, David Dede, lead security researcher at Sucuri Security, told SCMagazineUS.com on Friday.
“They [attackers] just started using a different site to host the malware, which is still live, so these sites are currently actively serving malware to their users,” Dede said.
Some of the same sites that were infected earlier this week were reinfected in the latest attack, he added. Since the second round of the attack just began, it is difficult to determine the extent, so the actual number of infected sites might be greater than 1,000.
The attack also has affected the websites: Ameristar.com; Servicewomen.org, which was also infected in the last wave of attacks, Booksellerandpublisher.com.au and Spain-holiday.com.
Ironically, one of the infected sites was Idera.com, a provider of SQL Server and SharePoint administration tools, Dede said.
Just like the last wave of attacks, all affected sites are hosted on Microsoft Internet Information Services (IIS) web servers, and using Active Server Pages software from ASP.net.
Earlier this week, Microsoft said the previous attack was the result of vulnerabilities in third-party web applications and did not demonstrate holes in Microsoft software.
Mary Landesman, a senior security researcher at Cisco, has said SQL injection attacks like this are common.