Microsoft Security Essentials (MSE) is an antivirus computer program that provides protection
against different types of malware such ascomputer viruses, spyware, rootkits and Trojan horses. It
uses the same antimalware foundation as other Microsoft antivirus products, although it lacks the
centralized management features of some of them. This product runs on Windows XP, Windows
Vista and Windows 7, but not on Windows 8, which has a built-in antivirus component. The
included license agreement allows home users and small businesses to install and use the
software free of charge.
The announcement of Microsoft Security Essentials icited mixed reactions from the antivirus
industry. Symantec, McAfee andKaspersky Lab, three competing independent software
vendors (ISVs), dismissed it as a worthy competitor and predicted its failure. AVG
Technologies and Avast Software, however, appreciated it for its potential to expand the consumers'
choice of antivirus software. Meanwhile, AVG, McAfee, Sophos and Trend Micro said that the
integration of Microsoft Security Essentials into Microsoft Windows would be a violation of competition
Despite the industry response, Microsoft Security Essentials has received generally positive reviews.
Reviewers praised its user-interface, low resource usage and freeware license. Microsoft Security
Essentials passed the antivirus lab tests of AV-TEST.org and secured AV-TEST.org certification,
having shown the ability to eliminate all widespread malware. According to OPSWAT Inc., on March
2012, Microsoft Security Essentials was the most popular antivirus product in North America and the
second most popular in the world. Due to its popularity, several rogue antivirus programs that try to
impersonate it have appeared.
o 2.1 Version 2.0
o 2.2 Version 4.0
o 2.3 Future
o 4.1 Industry response
o 4.2 Reviews
o 4.3 Awards
5 Market share
6 Rogue antivirus software
7 See also
9 External links
Microsoft Security Essentials is an antivirus product that fights malicious software (malware),
including computer viruses, spyware, Trojan horses and rootkits. The software runs on Windows
XP, Windows Vista and Windows 7. It replaces Windows Live OneCare, a discontinued
commercial subscription-based antivirus service and the free Windows Defender, which prior
to Windows 8, only protected users from adware and spyware.
Microsoft Security Essentials is built upon the same foundation as other Microsoft antimalware
products, all use the same virus definitionsand antimalware engine known as Microsoft Malware
Protection Engine (MSMPENG). Microsoft Security Essentials, however, lacks the personal
firewall or centralized management features found in OneCare or Forefront Endpoint
Microsoft Security Essentials' real-time protection feature constantly monitors file and program
activities on the computer, scanning new files as they are downloaded or created. Upon spotting a
threat, Microsoft Security Essentials disables the threat and prompts for user input. If no response is
received in ten minutes, then the suspected threat is handled according to the default actions defined
in theSettings section of the antivirus product. Depending on the settings, Microsoft Security
Essentials may create System Restore points before removing the detected malware. As a part of
real-time protection, Microsoft Security Essentials reports all suspicious behaviors of monitored
programs to Microsoft SpyNet, a web-based service. If the report matches a newly discovered
malware threat with an unreleased virus definition, Microsoft Security Essentials will download this
definition to remove the threat.
Microsoft Security Essentials relies on virus definitions to combat malware. It automatically checks for
and downloads virus definition updates which are published three times a day on Microsoft Update,
the web-based software update service. Alternatively, users may download the updates manually
from Microsoft Security Portal website.
According to Microsoft, hardware requirements for Microsoft Security Essentials differ, depending on
the operating system. On a computer with Windows XP, Microsoft Security Essentials requires at
least a 500 MHz processor and 256 MB of memory. On a Windows Vista or Windows 7 system,
Microsoft Security Essentials requires a 1 GHz processor and 1 GB of RAM. Microsoft Security
Essentials also needs a 800 × 600 pixels or larger display screen, 200 MB of free hard disk space and
an Internet connection.