Additional versions

6.2.8250.0 (winmain_win8beta.120217-1520)	0.37%
6.2.8102.0 (winmain_win8m3.110823-1455)	0.74%
4.3.9600.16384 (winblue_rtm.130821-1623)	13.01%
4.3.9600.16384 (winblue_rtm.130821-1623)	0.74%
4.3.9431.0 (winmain_bluemp.130615-1214)	1.86%
4.3.9431.0 (winmain_bluemp.130615-1214)	0.37%
4.0.9200.16384 (win8_rtm.120725-1247)	18.22%
4.0.9200.16384 (win8_rtm.120725-1247)	62.83%
4.0.8400.0 (winmain_win8rc.120518-1423)	1.12%
4.0.8400.0 (winmain_win8rc.120518-1423)	0.74%

This is a Windows system installed file with Windows File Protection (WFP) enabled.

MsMpEng.exe is the back-end of Microsoft Security Essentials. It is important to remember that this process is actually used by both Windows Defender and MSE. When you install Microsoft Security Essentials, then Windows Defender is automatically turned off and Microsoft Security Essentials uses this process. This is the main process that runs the program and takes quite some system memory. If you end this process then Microsoft Security Essentials will be disabled and an alert will be shown aski

CPU
Total CPU:	0.00051434%	0.028634%
Kernel CPU:	0.00038926%	0.013761%
User CPU:	0.00012509%	0.014873%
Kernel CPU time:	55,536,356 ms/min	100,923,805ms/min
Context switches:	258/sec	284/sec
Memory
Private memory:	72.34 MB	21.59 MB
Private (maximum):	78.5 MB
Private (minimum):	37.52 MB
Non-paged memory:	72.34 MB	21.59 MB
Virtual memory:	250.5 MB	140.96 MB
Virtual memory (peak):	545.46 MB	169.69 MB
Working set:	66.4 MB	18.61 MB
Working set (peak):	371.25 MB	37.95 MB
Resource allocations
Threads:	18	12
Handles:	474	600