According to AV-Test, an independent testing lab in Germany, Microsoft's Windows Defender security software, which comes bundled with Windows 8, barely passed a certification test, as of February 2013.
"We always used the most current publicly-available version of all products for the testing. They were allowed to update themselves at any time and query their in-the-cloud services. We focused on realistic test scenarios and challenged the products against real-world threats. Products had to demonstrate their capabilities using all components and protection layers," AV-TEST stated on their website.
Microsoft's Windows Defender lacked severely in the protection area (scoring a 2 out of 6 total points), while providing mediocre performance (3.5 out of 6) and excellent usability (6 out of 6). AV-TEST ranks the security software based on these three categories. The number one security solution? Bitdefender: Internet Security 2013 was ranked as number one while BullGuard and Kaspersky rounded off the top three.
AV-Test publishes test results every two months and usually looks at 25 different consumer antivirus security programs. Back in January of this year, Microsoft's Security Essentials, which is free for those who didn't know, lacked protection against 0-day malware attacks and detection of a representative set of malware discovered in the last 2-3 months, according to the test results. As a result, Microsoft's Security Essentials did not pass certification.