Attackers injected malicious code into Dailymotion.com, a popular video sharing website, and redirected visitors to Web-based exploits that installed malware.
The rogue code consisted of an iframe that appeared on Dailymotion on June 28, researchers from security vendor Symantec said Thursday in a blog post. The iframe redirected browsers to a different website hosting an installation of the Sweet Orange Exploit Kit, an attack tool that uses exploits for Java, Internet Explorer and Flash Player.
The flaws that Sweet Orange attempted to exploit are: CVE-2013-2551, patched by Microsoft in Internet Explorer in May 2013; CVE-2013-2460, patched by Oracle in Java in June 2013; and CVE-2014-0515, patched by Adobe in Flash Player in April.
"If the kit successfully exploited any of these vulnerabilities, then Trojan.Adclicker was downloaded onto the victim's computer," the Symantec researchers said. "This malware forces the compromised computer to artificially generate traffic to pay-per-click Web advertisements in order to generate revenue for the attackers."
It's not clear how long the attack lasted, but the code was no longer present on Dailymotion.com as of this week, according to the Symantec researchers. It's also not clear if the attack was the result of the website itself being hacked or a malicious advertisement served through a third-party ad network, a common method for inserting rogue code on popular websites.
Dailymotion did not immediately respond to a request for comment.
The video-sharing website ranks 90 on the list of top 100 most popular websites by traffic according to Amazon-owned Internet statistics firm Alexa. Symantec's data indicates that the majority of Dailymotion visitors affected by this attack were from the U.S. -- over 50 percent -- and Europe.
This is not the first time that Dailymotion.com has been used to distribute malware. In January, security firm Invincea reported that a malicious ad displayed on the site attempted to trick users into installing a fake antivirus program.