Change logs for security intelligence update version 1.449.228.0

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This page lists newly added and updated threat detections included in security intelligence updates for Microsoft Defender Antivirus and other Microsoft antimalware. If you don’t find the latest security intelligence update version in the selector below, please refresh this page or let us know us know through the feedback smiley.

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Security intelligence update version

Released on

4/21/2026 12:32:16 PM

Added threat detections

Name	Severity
Trojan:BAT/Obfuse.BAB!MTB	severe
Trojan:JS/Redirector.MDW!MTB	severe
Trojan:PowerShell/NetSupport.SB!MSR	severe
Trojan:VBS/StxRAT.SXR!MTB	severe
Trojan:Win32/NetSupportRat.ANR!MTB	severe
Trojan:Win32/Zusy.BAI!MTB	severe
Trojan:Win64/RustyStealer.VGX!MTB	severe
Trojan:Win64/ValleyRat.AKV!MTB	severe
Trojan:Win64/XWorm.VGX!MTB	severe
Trojan:Win64/XWorm.VGZ!MTB	severe
VirTool:Win64/MeterBof.A	severe
VirTool:Win64/MeterExtapi.A	severe
VirTool:Win64/MeterIncognito.A	severe
VirTool:Win64/MeterLan.A	severe
VirTool:Win64/MeterNcan.A	severe
VirTool:Win64/MeterPowerps.A	severe
VirTool:Win64/MeterPreInject.A	severe
VirTool:Win64/MeterShakti.A	severe
VirTool:Win64/MeterSlit.A	severe
VirTool:Win64/MeterSrvpip.A	severe

Updated threat detections

Name	Severity
Backdoor:Linux/BPFDoor.A!MTB	severe
Backdoor:MSIL/Caminho!AMTB	severe
Backdoor:MSIL/XWormRAT!rfn	severe
Backdoor:Win64/PortStarter!rfn	severe
Behavior:Linux/ExecutionFromSuspLocation.C	severe
BrowserModifier:Win32/MediaArena	high
HackTool:Linux/PthToolkitGen.ZZ	high
HackTool:MSIL/RunAs!MSR	high
HackTool:Win32/Broduplo!rfn	high
HackTool:Win32/Keygen	high
HackTool:Win32/Keygen!MTB	high
HackTool:Win32/Malgent!MSR	high
HackTool:Win32/Mimikatz!MSR	high
HackTool:Win32/Patcher!MTB	high
Joke:AndroidOS/Multiverze!rfn	moderate
Misleading:Win32/Lodi	high
MonitoringTool:Win32/MicTrayDebugger	severe
Ransom:BAT/BitLocker!rfn	severe
Ransom:MSIL/FileCoder.MX!MTB	severe
Ransom:Win32/Basta!rfn	severe
Ransom:Win32/Clop!rfn	severe
Ransom:Win32/ContiCrypt!rfn	severe
Ransom:Win32/Filecoder!rfn	severe
Ransom:Win32/Royal!rfn	severe
Ransom:Win64/FunkSec!rfn	severe
Ransom:Win64/Lynx!rfn	severe
Ransom:Win64/Mallox!rfn	severe
Trojan:AndroidOS/AVerseFalc!rfn	severe
Trojan:AndroidOS/Multiverze!rfn	severe
Trojan:BAT/Qakbot!rfn	severe
Trojan:HTML/FakeAlert!rfn	severe
Trojan:HTML/Nioc!rfn	severe
Trojan:HTML/Phish.LTF!MTB	severe
Trojan:HTML/Qakbot!rfn	severe
Trojan:HTML/ScrInject.SMW!MTB	severe
Trojan:JS/GuLoader.SPL!MTB	severe
Trojan:JS/IcedID!rfn	severe
Trojan:JS/Obfuse!MSR	severe
Trojan:JS/QakbotLNK!rfn	severe
Trojan:JS/Redirector.TSE!MTB	severe
Trojan:JS/SpyBanker.GPTE!MTB	severe
Trojan:Linux/CoinMiner!rfn	severe
Trojan:Linux/Multiverze!rfn	severe
Trojan:MSIL/Menorah.AMN!MTB	severe
Trojan:O97M/DDownloader!rfn	severe
Trojan:PDF/Qakbot!rfn	severe
Trojan:PowerShell/PowDown!rfn	severe
Trojan:Python/Bobik.EB!MTB	severe
Trojan:Python/Nuitka!MTB	severe
Trojan:Python/Stealer.SKB!MTB	severe
Trojan:Script/Multiverze!rfn	severe
Trojan:VBS/Obfuse!MSR	severe
Trojan:VBS/Qakbot!rfn	severe
Trojan:Win32/Acll!rfn	severe
Trojan:Win32/Alevaul!rfn	severe
Trojan:Win32/Amadey!rfn	severe
Trojan:Win32/AutoitInject.DSK!MTB	severe
Trojan:Win32/Casdet!rfn	severe
Trojan:Win32/Cerber!rfn	severe
Trojan:Win32/CleanUpLoaderLNK!rfn	severe
Trojan:Win32/Convagent!rfn	severe
Trojan:Win32/CoreWarrior.DA!MTB	severe
Trojan:Win32/Coroxy!rfn	severe
Trojan:Win32/CryptInject!MSR	severe
Trojan:Win32/Dacic.SX!MTB	severe
Trojan:Win32/DarkGate!rfn	severe
Trojan:Win32/DllInject!rfn	severe
Trojan:Win32/Egairtigado!rfn	severe
Trojan:Win32/Ekstak!rfn	severe
Trojan:Win32/Fauppod!rfn	severe
Trojan:Win32/Filecoder!rfn	severe
Trojan:Win32/IcedIdLNK!rfn	severe
Trojan:Win32/ICLoader.RND!MTB	severe
Trojan:Win32/Kazadm.A!MTB	severe
Trojan:Win32/Kepavll!rfn	severe
Trojan:Win32/Leonem!rfn	severe
Trojan:Win32/Malgent	severe
Trojan:Win32/Malgent!MSR	severe
Trojan:Win32/Malgent!rfn	severe
Trojan:Win32/MereTam!rfn	severe
Trojan:Win32/Persistence	severe
Trojan:Win32/PhishLeonem!rfn	severe
Trojan:Win32/Pomal!rfn	severe
Trojan:Win32/Qakbot!rfn	severe
Trojan:Win32/Qwexlafiba!rfn	severe
Trojan:Win32/Ravartar!rfn	severe
Trojan:Win32/Seheq!rfn	severe
Trojan:Win32/ShortcutFileInZipExec!rfn	severe
Trojan:Win32/SmokeLoader.FT!MTB	severe
Trojan:Win32/Supma.A	severe
Trojan:Win32/Suschil!rfn	severe
Trojan:Win32/SystemBC!rfn	severe
Trojan:Win32/Tnega!MSR	severe
Trojan:Win32/Vindor!rfn	severe
Trojan:Win32/Yomal!rfn	severe
Trojan:Win32/Zloader!rfn	severe
Trojan:Win32/Znyonm!rfn	severe
Trojan:Win64/AsyncRat!rfn	severe
Trojan:Win64/BruteRatel!rfn	severe
Trojan:Win64/CryptInject!rfn	severe
Trojan:Win64/Donut!rfn	severe
Trojan:Win64/Emotetcrypt!rfn	severe
Trojan:Win64/EmotetPacker!rfn	severe
Trojan:Win64/IcedID!rfn	severe
Trojan:Win64/Jalapeno.ARR!MTB	severe
Trojan:Win64/Latrodectus!rfn	severe
Trojan:Win64/Lazy!MTB	severe
Trojan:Win64/Lazy.SXQ!MTB	severe
Trojan:Win64/Malgent!MSR	severe
Trojan:Win64/Malgent!MTB	severe
Trojan:Win64/NightHawk!rfn	severe
Trojan:Win64/Oyster!rfn	severe
Trojan:Win64/XWorm.VGY!MTB	severe
Trojan:Win64/Zusy.PGZI!MTB	severe
TrojanDownloader:BAT/QakBotLoader!rfn	severe
TrojanDownloader:JS/Qakbot!rfn	severe
TrojanDownloader:O97M/Emotet!rfn	severe
TrojanDownloader:PowerShell/Obfuse!rfn	severe
TrojanDownloader:Win32/Citeary!rfn	severe
VirTool:Java/Donk!ldr	severe
VirTool:Win32/Sliver!rfn	severe
VirTool:WinNT/Rootkitdrv!rfn	severe
Worm:Win32/AutoRun!rfn	severe
Worm:Win32/Brontok!rfn	severe
Worm:Win32/Citeary!rfn	severe