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Microsoft Defender Antivirus

Microsoft Defender Antivirus is the built-in antimalware software on Windows, providing real-time scanning, threat detection, and signature-based protection.

Known aliases

  • Defender Antivirus
  • MDAV
  • Microsoft Defender
  • MsMpEng.exe

Current stories

securityOne report1 publisher

Attackers hide malware from Microsoft Defender by adding scan exclusions

Huntress details four ways attackers who already hold administrator rights add Microsoft Defender exclusions to keep malicious files out of every scan. A registry value can also hide those exclusions from any admin who checks for them.

Publishers:huntress.com

Reality

Evidence58
Adoption
Not scored
Hype gap+8
Incentives62
Confidence60
buildOne report1 publisher

BigDiskBuster reserves the last free bytes on C: to make Defender updates fail

The public proof-of-concept watches Defender's update directories, hoards nearly all the free space on C: with delete-on-close files, and hands the space back once the update has already failed. At rest, the disk looks normal.

Publishers:dev.to

Reality

Evidence36
Adoption12
Hype gap+34
Incentives
Not scored
Confidence42
securityOne report1 publisher

Microsoft's September 17 Defender update ends the false 'antivirus is turned off' notifications

Defender Antivirus 4.18.26080.4 fixes notifications that told users the antivirus was off while it was still scanning. The bug reached every supported Windows client and server build and had been visible in Release Preview since June.

Reality

Evidence72
Adoption55
Hype gap−8
Incentives45
Confidence74
securityOne report1 publisher

Microsoft's August security update kept Teams off freshly imaged ARM Surfaces for 28 days

The security update released on August 11 stopped Microsoft Teams and the new Outlook launching on ARM Surfaces that had never taken a Microsoft Store update. Microsoft shipped the fix on September 8.

Reality

Evidence68
Adoption45
Hype gap+12
Incentives55
Confidence66
securityOne report1 publisher

The refund scam that asks you to uninstall your antivirus, then writes down which one

Eleven look-alike sites run a scan whose score is capped at 30 out of 100, then record which of 28 security products the victim removed. Endpoint tampering by consent, over the phone.

Publishers:malwarebytes.com

Reality

Evidence74
Adoption24
Hype gap+8
Incentives72
Confidence64