Updated Microsoft has admitted its Windows Live Messenger client displayed banner ads for several days punting an application blacklisted as a security risk. Shortly after Microsoft made the admission, other outlets reported that MSN Groups displayed ads for a separate piece of software widely regarded as rogue.
Redmond has pulled the ads for Errorsafe, a purported security product labeled by legitimate firms as "scareware" designed to frighten users into buying a product that actually impairs internet safety. Redmond has promised to review its advertisement approval process in order to prevent the problem cropping up again.
For a period earlier this week, Errorsafe, which is listed as a security risk alongside related packages such as Winfixer, appeared as a banner ad inside Windows Live Messenger.
Worse still, pop-up ads punting the product were served to users running Windows Live Messenger. These pop-up ads appeared without user interaction. Clicking on the OK or Cancel buttons in this pop-up window would have resulted in an attempt to download a malicious ActiveX control without a user's permission.
In another incident involving rogue software, Microsoft has also apologized after its MSN Groups was caught serving ads hawking SystemDoctor2006, according to APC Mag.
The Microsoft-distributed ads give a veneer of legitimacy to packages that advise surfers they are infected with spyware, whether they are or not, in an attempt to hoodwink users into buying ineffective software.
"We immediately investigated the reports and removed the offending ads, as this is a violation of our ad-serving policy," Microsoft spokeswoman Whitney Burk told IDG.
The incident is the second time adverts for potentially unwanted programs have made their way onto the ad serving networks servicing well-known internet brands over recent weeks. MySpace served up banner ads for AntiVirus Pro and DriveCleaner, other so-called security packages that offer nothing but misery for users, in January.
Sandi Hardmeier, a Microsoft Most Valued Professional who was the first to document the Errorsafe on Messenger threat, said Microsoft has let itself and its users badly down over failing to block the offending ads.
"For years I have been holding up MSN Messenger banner advertisements as an example of how advertisements can be safely served up to end users without putting them at risk of malware," she writes on her Spyware Sucks blog.
"Now, everything has changed. Users have been put at direct risk through no fault of their own and they can't avoid the MSN banner advertisements when the contact pane is open without using a third party hack that is ethically wrong to use." ®