New outbreak of malicious adverts detected

Attacks have targetted high-profile sites such as Drudge

Security researchers have detected a new wave of malicious adverts that have been attacking users as recently as this week.

Security firm ScanSafe said the attacks had been serving up exploits for a three-day period from 19 to 21 September. The company said that the infected banners were displayed on a number of prominent web sites, including the Drudge Report and Lyrics.com.

According to ScanSafe, the banner ads had been embedded with code that referenced third-party attack sites. The attack sites then attempted to exploit both PDF and ActiveX browser vulnerabilities to install a trojan downloader, which in turn summoned malware to log search data and redirect web traffic.

The company said that the attacks were not unique and that similar cases have been spotted since July. The company noted, however, that the malware used for the PDF attacks was particularly hard for security software to detect.

The rise of malicious ad banners or 'malvertising' has led Google to take action to protect its advertising partners.

The attacks usually involve Malware writers embedding seemingly legitimate banner ads with small amounts of code that reference remote attack sites. The result is an advertisement that can cause otherwise legitimate sites to unknowingly put their visitors at risk of infection.

Earlier this week, Microsoft said that it would be suing several companies it believes to be behind numerous malvertising attacks on its advertising networks.