The Italian job that last month saw more than 10,000 legit Web pages embedded with malicious IFrames has resurfaced, this time with even more international intrigue. Last month's threat pushed malicious HTML files onto Web pages of several Italian Web sites and infected Web surfers visiting those sites. The new threat comes from a number of newly registered Web sites that pretend to represent Italian organizations, but are really just vehicles for using malicious IFrames to spread malware.
Indeed, these new sites aren't even being hosted in Italy; they're being hosted out of Germany and may be tied to Russian malware writers, Trend Micro network architect Paul Ferguson told InformationWeek. "One of our researchers found an IP address that included 400 pieces of malware on different URLs," he said.
As of Friday morning, about 2,500 systems may have been infected by these malicious IFrames. "Not an astounding number," Ferguson acknowledged, "but the number is apparently growing." Trend Micro's investigation is ongoing.
An IFrame, or inline frame, makes it possible to embed one HTML document inside another HTML document. Victims of the first attack in June were people visiting Web sites hosted in Italy for Italian city councils, employment services, and tourism sites. Attackers embedded IFrames into these sites. When site visitors clicked on these malicious IFrames their computers were infected.
Trend Micro came across the new Web sites while the company's researchers were doing their daily analysis of their honeypot and proxy logs, which are placed out on the Internet and made to look like open proxies or unpatched systems ripe for attack. "We saw certain IP addresses and domain names that raised a red flag," Ferguson said. This included the movement of domains from one domain name server to another, a move that's typically associated with an attempt to avoid detection. These new sites containing malicious IFrames create layers of obfuscation that make it difficult to determine who's behind the sites.
While Trend Micro's research isn't comprehensive enough at this time to send law enforcement busting through anyone's door, it's detection of these new sites laden with malicious IFrames comes before the problem "managed to fully blossom," Ferguson said. "We're making these guys go through a lot of trouble for nothing."
It's not so much that the malware threat is different; it's similar to the one that surfaced last month in that it looks to exploit unpatched PCs. Instead, this new scheme represents an evolution of the delivery mechanism for malware. To counter these emerging methods, security vendors need to rely less on building up already bulky blacklists or adding signatures to malware filters. As cybercriminals become more experimental, it's the ability to trace these malicious sites back to their source that's going to make the difference in fighting cyber attacks, Ferguson said.