Hackers are using a new multiple-attack package composed of seven ActiveX exploits, many of them never seen in the wild before, said a security company.
Fewer than half of the flawed ActiveX controls have been patched.
The attack framework probes Windows PCs for vulnerable ActiveX controls from software vendors Microsoft, Citrix Systems and Macrovision, as well as hardware makers D-Link, Hewlett-Packard, Gateway,and Sony, said a Symantec researcher.
"What's interesting about this attack is that there are so many vulnerabilities in one attack that have not been seen in the wild previously," said Symantec's Patrick Jungles, who wrote an analysis of the multi-strike package for customers of the company's DeepSight threat service.
According to Jungles, visitors to compromised Web sites are redirected by a rogue IFRAME to a malicious site serving the package. The attack pack tests the victim's PC for each ActiveX control, detects whether a vulnerable version of a control is installed, then launches an attack when it finds one.
Bugs in ActiveX, a Microsoft technology used most often to create add-ons for the company's Internet Explorer (IE) browser, have always been common, but so many serious flaws have been disclosed of late that some security experts have recommended users do without them.
The seven exploited in the package outlined by Jungles are a mix of old and brand-new flaws. For example, Microsoft's own ActiveX vulnerability -- a bug in IE's Speech API (application programming interface) -- was disclosed in June 2007, while the vulnerability in the Citrix Presentation Server Client control harks back even further, to December 2006. Others, such as the ActiveX bugs in D-Link's security Webcams and in Sony's ImageStation, are much more recent, having been revealed in February.
Four of the seven ActiveX flaws -- those in the D-Link, Gateway, Sony and Macrovision products -- have not been patched, said Jungles.
Assuming the exploit framework succeeds in compromising a PC, the hackers drop a Trojan on the machine that turns it into a spam-spewing zombie; the Trojan includes a rootkit component to mask the malware from anti-virus scanners.
Symantec added that while the initial IP address that sent users to the malicious site was no longer infected with the IFRAME code, other addresses were redirecting users.
"The list of IPs involved in the exploitation is by no means comprehensive," said Jungles, "because the nature of the exploitation indicates that several other sites are likely forwarding victims." The IFRAME code, he continued, had been found embedded in the legitimate sites' HTML and was at times distributed via online advertisements; DNS poisoning, he said, was also suspected.
Jungles' report recommended that users apply patches, when they're available, and set the "kill bit" on those ActiveX controls which have not yet been updated by their makers.