Microsoft security researchers have identified critical vulnerabilities in Facebook and Google Picase which led to account compromise and arbitrary code execution.
The bug in Picasa that the MVR team found could allow an attacker to gain complete control of a user's machine if he could entice the victim into downloading a malicious JPEG file. It's not the most complex exploitation scenario, and in the current age of people sharing, downloading, emailing and re-posting photos on a variety of platforms, it might not be too difficult for an attacker to accomplish.
"A vulnerability exists in the way that Picasa handles certain specially crafted JPEG images. An attacker could exploit this vulnerability to cause Picasa to exit unexpectedly and execute arbitrary code. An attacker who successfully exploited this vulnerability could gain the same user rights as the logged-on user. If a user is logged on with administrative user rights, an attacker who successfully exploited this vulnerability could take complete control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights," Microsoft said in its advisory.
The vulnerability in Facebook involves a problem with the way that the site implemented its protection against clickjacking attacks. An attacker could use the vulnerability to gain full access to a victim's account.
UPDATE : Facebook has fixed the problem, Just after release of Advisory.