A wave of bugs in the plug-in technology used by Microsoft 's Internet Explorer (IE) browser has led some security experts, including those at US_CERT, recommending that users disable all ActiveX controls.
The US Computer Emergency Readiness Team (US-CERT), part of the government's Department of Homeland Security, was explicit in advisories posted this week: "US-CERT encourages users to disable ActiveX controls,” it stated.
US-CERT's advice was prompted by multiple vulnerabilities in high-profile ActiveX components used by members of the popular Facebook and MySpace social networks, as well as users of Yahoo Inc.'s music services.
Three new vulnerabilities in the photo uploader software used by both Facebook and MySpace were disclosed Monday by researcher Elezar Broad, who on Monday also posted sample attack code for a pair of critical bugs in Yahoo's Music Jukebox.
Last week, Broad had pinned the Facebook and MySpace ActiveX controls with two other flaws.
As the number of vulnerabilities mounted, security professionals began ringing the alarm. On Monday, for instance, Symantec analysts urged users to "use caution when browsing the Web" and told IT administrators to disable the relevant ActiveX controls by setting several "kill bits" in the Windows registry.
US-CERT, however, offered up more aggressive advice as it recommended users move IE's security level to the "High" setting, which completely disables all ActiveX controls.
"That is the easiest way to protect yourself," agreed Oliver Friedrichs, director of Symantec Corp.'s security response group. "But it can also have an adverse impact on your browsing experience." A compromise, said Friedrichs, would be to disable "only those plug-ins that pose a current and imminent threat," such as the flawed ActiveX controls used by Facebook, MySpace and Yahoo.
"That approach is hard to argue against in the enterprise," said Friedrichs, who noted that there are tools available that let corporate IT administrators push registry changes - including new keys that disable specific ActiveX controls - to all users.
Browser plug-in problems are not rare, said Friedrichs. "In the first half of 2007, Symantec counted 237 plug-in vulnerabilities. That's compared to 108 in all of 2006." Some 89% were in ActiveX controls, making IE by far the most popular target for plug-in exploits.