The five-day job: A BlackByte ransomware intrusion case study

As ransomware attacks continue to grow in number and sophistication, threat actors can quickly impact business operations if organizations are not well prepared. In a recent investigation by Microsoft Incident Response (previously known as Microsoft Detection and Response Team – DART) of an intrusion, we found that the threat actor progressed through the full attack chain, from initial access to impact, in less than five days, causing significant business disruption for the victim organization.

Our investigation found that within those five days, the threat actor employed a range of tools and techniques, culminating in the deployment of BlackByte 2.0 ransomware, to achieve their objectives. These techniques included:

  • Exploitation of unpatched internet-exposed Microsoft Exchange Servers
  • Web shell deployment facilitating remote access
  • Use of living-off-the-land tools for persistence and reconnaissance
  • Deployment of Cobalt Strike beacons for command and control (C2)
  • Process hollowing and the use of vulnerable drivers for defense evasion
  • Deployment of custom-developed backdoors to facilitate persistence
  • Deployment of a custom-developed data collection and exfiltration tool
BlackByte 2.0 ransomware attack chain by order of stages: initial access and privilege escalation, persistence and command and control, reconnaissance, credential access, lateral movement, data staging and exfiltration, and impact.
Figure 1. BlackByte 2.0 ransomware attack chain

In this blog, we share details of our investigation into the end-to-end attack chain, exposing security weaknesses that the threat actor exploited to advance their attack. As we learned from Microsoft's tracking of ransomware attacks and the cybercriminal economy that enables them, disrupting common attack patterns could stop many of the attacker activities that precede ransomware deployment. This case highlights that common security hygiene practices go a long way in preventing, identifying, and responding to malicious activity as early as possible to mitigate the impact of ransomware attacks. We encourage organizations to follow the outlined mitigation steps, including ensuring that internet-facing assets are up to date and configured securely. We also share indicators of compromise, detection details, and hunting guidance to help organizations identify and respond to these attacks in their environments.

Forensic analysis

Initial access and privilege escalation

To obtain initial access into the victim's environment, the threat actor was observed exploiting the ProxyShell vulnerabilities CVE-2021-34473, CVE-2021-34523, and CVE-2021-31207 on unpatched Microsoft Exchange Servers. The exploitation of these vulnerabilities allowed the threat actor to:

  • Attain system-level privileges on the compromised Exchange host
  • Enumerate LegacyDN of users by sending Autodiscover requests, including SIDs of users
  • Construct a valid token and use it against the Exchange PowerShell backend
  • Impersonate domain admin users and create a web shell by using the New-MailboxExportRequest cmdlet
  • Create web shells to obtain remote control on affected servers

The threat actor was observed operating from the following IP to exploit ProxyShell and access the web shell:

  • 185.225.73[.]244



After gaining access to a device, the threat actor created the following registry run keys to run a payload each time a user signs in:

Registry key Value name Value data
HKEY_CURRENT_USERSoftwareMicrosoftWindowsCurrentVersionRun   MsEdgeMsE rundll32 C:UsersuserDownloadsapi-msvc.dll,Default  
HKEY_CURRENT_USERSoftwareMicrosoftWindowsCurrentVersionRun   MsEdgeMsE rundll32 C:tempapi-msvc.dll,Default  
HKEY_CURRENT_USERSoftwareMicrosoftWindowsCurrentVersionRun   MsEdgeMsE rundll32 C:systemtestapi-system.png,Default

The file api-msvc.dll (SHA-256: 4a066569113a569a6feb8f44257ac8764ee8f2011765009fdfd82fe3f4b92d3e) was determined to be a backdoor capable of collecting system information, such as the installed antivirus products, device name, and IP address. This information is then sent via HTTP POST request to the following C2 channel:

  • hxxps://myvisit[.]alteksecurity[.]org/t

The organization was not using Microsoft Defender Antivirus, which detects this malware as Trojan:Win32/Kovter!MSR, as the primary antivirus solution, and the backdoor was allowed to run.

An additional file, api-system.png, was identified to have similarities to api-msvc.dll. This file behaved like a DLL, had the same default export function, and also leveraged run keys for persistence.

Cobalt Strike Beacon

The threat actor leveraged Cobalt Strike to achieve persistence. The file sys.exe (SHA-256: 5f37b85687780c089607670040dbb3da2749b91b8adc0aa411fd6280b5fa7103), detected by Microsoft Defender Antivirus as Trojan:Win64/CobaltStrike!MSR, was determined to be a Cobalt Strike Beacon and was downloaded directly from the file sharing service temp[.]sh:

  • hxxps://temp[.]sh/szAyn/sys.exe

This beacon was configured to communicate with the following C2 channel:

  • 109.206.243[.]59:443


Threat actors leverage legitimate remote access tools during intrusions to blend into a victim network. In this case, the threat actor utilized the remote administration tool AnyDesk, to maintain persistence and move laterally within the network. AnyDesk was installed as a service and was run from the following paths:

  • C:systemtestanydeskAnyDesk.exe
  • C:Program Files (x86)AnyDeskAnyDesk.exe
  • C:ScriptsAnyDesk.exe

Successful connections were observed in the AnyDesk log file ad_svc.trace involving anonymizer service IP addresses linked to TOR and MULLVAD VPN, a common technique that threat actors employ to obscure their source IP ranges.


We found the presence and execution of the network discovery tool NetScan being used by the threat actor to perform network enumeration using the following file names:

  • netscan.exe (SHA-256:1b9badb1c646a19cdf101ac4f6fdd23bc61eaab8c9f925eb41848cea9fd0738e)
  • netapp.exe (SHA-256:1b9badb1c646a19cdf101ac4f6fdd23bc61eaab8c9f925eb41848cea9fd0738e)

Additionally, execution of AdFind (SHA-256: f157090fd3ccd4220298c06ce8734361b724d80459592b10ac632acc624f455e), an Active Directory reconnaissance tool, was observed in the environment.

Credential access

Evidence of likely usage of the credential theft tool Mimikatzwas also uncovered through the presence of a related log file mimikatz.log. Microsoft IR assesses that Mimikatz was likely used to attain credentials for privileged accounts.

Lateral movement

Using compromised domain admin credentials, the threat actor used Remote Desktop Protocol () and PowerShell remoting to obtain access to other servers in the environment, including domain controllers.

Data staging and exfiltration

In one server where Microsoft Defender Antivirus was installed, a suspicious file named explorer.exe was identified, detected as Trojan:Win64/WinGoObfusc.LK!MT, and quarantined. However, because tamper protection wasn't enabled on this server, the threat actor was able to disable the Microsoft Defender Antivirus service, enabling the threat actor to run the file using the following command:

explorer.exe P@$$w0rd

After reverse engineering explorer.exe, we determined it to be ExByte, a GoLang-based tool developed and commonly used in BlackByte ransomware attacks for collection and exfiltration of files from victim networks. This tool is capable of enumerating files of interest across the network and, upon execution, creates a log file containing a list of files and associated metadata. Multiple log files were uncovered during the investigation in the path:

  • C:ExchangeMSExchLog.log

Analysis of the binary revealed a list of file extensions that are targeted for enumeration.

Figure 2. Binary analysis showing file extensions enumerated by explorer.exe

Forensic analysis identified a file named data.txt that was created and later deleted after ExByte execution. This file contained obfuscated credentials that ExByte leveraged to authenticate to the popular file sharing platform Mega NZ using the platform's API at:

  • hxxps://[.]nz
Figure 3. Binary analysis showing explorer.exe functionality for connecting to file sharing service MEGA NZ

We also determined that this version of Exbyte was crafted specifically for the victim, as it contained a hardcoded device name belonging to the victim and an internal IP address.

ExByte execution flow

Upon execution, ExByte decodes several strings and checks if the process is running with privileged access by reading .PHYSICALDRIVE0:

  • If this check fails, ShellExecuteW is invoked with the IpOperation parameter RunAs, which runs explorer.exe with elevated privileges.

After this access check, explorer.exe attempts to read the data.txt file in the current location:

  • If the text file doesn't exist, it invokes a command for self-deletion and exits from memory:
C:Windowssystem32cmd.exe /c ping -n 10 > nul & Del explorer.exe /F /Q
  • If data.txt exists, explorer.exe reads the file, passes the buffer to Base64 decode function, and then decrypts the data using the key provided in the command line. The decrypted data is then parsed as JSON below and fed for login function:

Finally, it forms a URL for sign-in to the API of the service MEGA NZ:

  • hxxps://[.]nz/cs?id=1674017543

Data encryption and destruction

On devices where files were successfully , we identified suspicious executables, detected by Microsoft Defender Antivirus as Trojan:Win64/BlackByte!MSR, with the following names:

  • wEFT.exe
  • schillerized.exe

The files were analyzed and determined to be BlackByte 2.0 binaries responsible for across the environment. The binaries require an 8-digit key number to encrypt files.

Two modes of execution were identified:

  • When the -s parameter is provided, the ransomware self-deletes and encrypts the machine it was executed on.
  • When the -a parameter is provided, the ransomware conducts enumeration and uses an Ultimate Packer Executable (UPX) packed version of PsExec to deploy across the network. Several domain admin credentials were hardcoded in the binary, facilitating the deployment of the binary across the network.

Depending on the switch (-s or -a), execution may create the following files:

  • C:SystemDataM8yl89s7.exe (UPX-packed PsExec with a random name; SHA-256: ba3ec3f445683d0d0407157fda0c26fd669c0b8cc03f21770285a20b3133098f)
  • C:SystemDatawEFT.exe (Additional BlackByte binary)
  • C:SystemDataMsExchangeLog1.log (Log file)
  • C:SystemDatarENEgOtiAtES (A vulnerable (CVE-2019-16098) driver RtCore64.sys used to evade detection by installed antivirus software; SHA-256: 01aa278b07b58dc46c84bd0b1b5c8e9ee4e62ea0bf7a695862444af32e87f1fd)
  • C:SystemDataiHu6c4.ico (Random name – BlackBytes icon)
  • C:SystemDataBB_Readme_file.txt (BlackByte ReadMe file)
  • C:SystemDataskip_bypass.txt (Unknown)

BlackByte 2.0 ransomware capabilities

Some capabilities identified for the BlackByte 2.0 ransomware were:

  • Antivirus bypass
    • The file rENEgOtiAtES created matches RTCore64.sys, a vulnerable driver (CVE-2049-16098) that allows any authenticated user to read or write to arbitrary memory
    • The BlackByte binary then creates and starts a service named RABAsSaa calling rENEgOtiAtES, and exploits this service to evade detection by installed antivirus software
  • Process hollowing
    • Invokes svchost.exe, injects to it to complete device encryption, and self-deletes by executing the following command:
      • cmd.exe /c ping -n 10 > Nul & Del “PATH_TO_BLACKBYTE” /F /Q
  • Modification / disabling of Windows Firewall
    • The following commands are executed to either modify existing Windows Firewall rules, or to disable Windows Firewall entirely:
      • cmd /c netsh advfirewall set allprofiles state off
      • cmd /c netsh advfirewall firewall set rule group=”File and Printer Sharing” new enable=Yes
      • cmd /c netsh advfirewall firewall set rule group=”Network Discovery” new enable=Yes
  • Modification of volume shadow copies
    • The following commands are executed to destroy volume shadow copies on the machine:
      • cmd /c vssadmin Resize ShadowStorge /For=B: /On=B: /MaxSize=401MB
      • cmd /c vssadmin Resize ShadowStorage /For=B: /On=B: /MaxSize=UNBOUNDED
  • Modification of registry keys/values
    • The following commands are executed to modify the registry, facilitating elevated execution on the device:
      • cmd /c reg add HKLMSOFTWAREMicrosoftWindowsCurrentVersionPoliciesSystem /v LocalAccountTokenFilterPolicy /t REG_DWORD /d 1 /f
      • cmd /c reg add HKLMSOFTWAREMicrosoftWindowsCurrentVersionPoliciesSystem /v EnableLinkedConnections /t REG_DWORD /d 1 /f
      • cmd /c reg add HKLMSYSTEMCurrentControlSetControlFileSystem /v LongPathsEnabled /t REG_DWORD /d 1 /f
  • Additional functionality
    • Ability to terminate running services and processes
    • Ability to enumerate and mount volumes and network shares for encryption
    • Perform anti-forensics technique timestomping (sets the file time of and ReadMe file to 2000-01-01 00:00:00)
    • Ability to perform anti-debugging techniques


To guard against BlackByte ransomware attacks, Microsoft recommends the following:

  • Ensure that you have a patch management process in place and that patching for internet-exposed devices is prioritized; Understand and assess your cyber exposure with advanced vulnerability and configuration assessment tools like Microsoft Defender Vulnerability Management
  • Implement an endpoint detection and response (EDR) solution like Microsoft Defender for Endpoint to gain visibility into malicious activity in real time across your network
  • Ensure antivirus protections are updated regularly by turning on cloud-based protection and that your antivirus solution is configured to block threats
  • Enable tamper protection to prevent components of Microsoft Defender Antivirus from being disabled
  • Block inbound traffic from IPs specified in the indicators of compromise section of this report
  • Block inbound traffic from TOR exit nodes
  • Block inbound access from unauthorized public VPN services
  • Restrict administrative privileges to prevent authorized system changes


BlackByte ransomware attacks target organizations that have infrastructure with unpatched vulnerabilities.  As outlined in the Microsoft Digital Defense Report, common security hygiene practices, including keeping systems up to date, could protect against 98% of attacks.

As new tools are being developed by threat actors, a modern threat protection solution like Microsoft 365 Defender is necessary to prevent and detect the multiple techniques used in the attack chain, especially where the threat actor attempts to evade or disable specific defense mechanisms. Hunting for malicious behavior should be performed regularly in order to detect potential attacks that could evade detections, as a complementary activity for continuous monitoring from security tools alerts and incidents.

To understand how Microsoft can help you secure your network and respond to network compromise, visit

Microsoft 365 Defender detections

Microsoft Defender Antivirus

Microsoft Defender Antivirus detects this threat as the following malware:

  • Trojan:Win32/Kovter!MSR
  • Trojan:Win64/WinGoObfusc.LK!MT
  • Trojan:Win64/BlackByte!MSR
  • HackTool:Win32/AdFind!MSR
  • Trojan:Win64/CobaltStrike!MSR

Microsoft Defender for Endpoint

The following alerts might indicate threat activity related to this threat. Note, however, that these alerts can be also triggered by unrelated threat activity.

  • ‘CVE-2021-31207' exploit malware was detected
  • An active ‘NetShDisableFireWall' malware in a command line was prevented from executing.
  • Suspicious registry modification.
  • ‘Rtcore64' hacktool was detected
  • Possible ongoing hands-on-keyboard activity (Cobalt Strike)
  • A file or network connection related to a ransomware-linked emerging threat activity group detected
  • Suspicious sequence of exploration activities
  • A process was injected with potentially malicious code
  • Suspicious behavior by cmd.exe was observed
  • ‘Blackbyte' ransomware was detected

Microsoft Defender Vulnerability Management

Microsoft Defender Vulnerability Management surfaces devices that may be affected by the following vulnerabilities used in this threat:

  • CVE-2021-34473
  • CVE-2021-34523
  • CVE-2021-31207
  • CVE-2019-16098

Hunting queries

Microsoft 365 Defender

Microsoft 365 Defender customers can run the following query to find related activity in their networks:

ProxyShell web shell creation events

| where ProcessCommandLine has_any ("ExcludeDumpster","New-ExchangeCertificate") and ProcessCommandLine has_any ("-RequestFile","-FilePath")

Suspicious vssadmin events

| where ProcessCommandLine has_any ("vssadmin","vssadmin.exe") and ProcessCommandLine has "Resize ShadowStorage" and ProcessCommandLine has_any ("MaxSize=401MB"," MaxSize=UNBOUNDED")

Detection for persistence creation using Registry Run keys

| where ActionType == "RegistryValueSet"
| where (RegistryKey has @"MicrosoftWindowsCurrentVersionRunOnce" and RegistryValueName == "MsEdgeMsE")
    or (RegistryKey has @"MicrosoftWindowsCurrentVersionRunOnceEx" and RegistryValueName == "MsEdgeMsE")
    or (RegistryKey has @"MicrosoftWindowsCurrentVersionRun" and RegistryValueName == "MsEdgeMsE")
| where RegistryValueData startswith @"rundll32"
| where RegistryValueData endswith @".dll,Default"
| project Timestamp,DeviceId,DeviceName,ActionType,RegistryKey,RegistryValueName,RegistryValueData

Microsoft Sentinel

Microsoft Sentinel customers can use the TI Mapping analytics (a series of analytics all prefixed with ‘TI map') to automatically match the malicious domain indicators mentioned in this blog post with data in their workspace. If the TI Map analytics are not currently deployed, customers can install the solution from the Microsoft Sentinel Content Hub to have the analytics rule deployed in their Sentinel workspace. More details on the Content Hub can be found here:

Microsoft Sentinel also has a range of detection and threat hunting content that customers can use to detect the post exploitation activity detailed in this blog in addition to Microsoft 365 Defender detections list above.

Indicators of compromise

The table below shows IOCs observed during our investigation. We encourage our customers to investigate these indicators in their environments and implement detections and protections to identify past related activity and prevent future attacks against their systems.

Indicator Type Description
4a066569113a569a6feb8f44257ac8764ee8f2011765009fdfd82fe3f4b92d3e SHA-256 api-msvc.dll (Backdoor installed through RunKeys)
5f37b85687780c089607670040dbb3da2749b91b8adc0aa411fd6280b5fa7103 SHA-256 sys.exe (Cobalt Strike Beacon)
01aa278b07b58dc46c84bd0b1b5c8e9ee4e62ea0bf7a695862444af32e87f1fd SHA-256 rENEgOtiAtES (Vulnerable driver RtCore64.sys created by BlackByte binary)
ba3ec3f445683d0d0407157fda0c26fd669c0b8cc03f21770285a20b3133098f SHA-256 [RANDOM_NAME].exe (UPX Packed PsExec created by BlackByte binary)
1b9badb1c646a19cdf101ac4f6fdd23bc61eaab8c9f925eb41848cea9fd0738e SHA-256 “netscan.exe”, “netapp.exe (Netscan network discovery tool)
f157090fd3ccd4220298c06ce8734361b724d80459592b10ac632acc624f455e SHA-256 AdFind.exe (Active Directory information gathering tool)
hxxps://myvisit[.]alteksecurity[.]org/t URL C2 for backdoor api-msvc.dll
hxxps://temp[.]sh/szAyn/sys.exe URL Download URL for sys.exe
109.206.243[.]59 IP Address C2 for Cobalt Strike Beacon sys.exe
185.225.73[.]244 IP Address Originating IP address for ProxyShell exploitation and web shell interaction

NOTE: These indicators should not be considered exhaustive for this observed activity.


File extensions targeted by BlackByte binary for encryption:

.4dd .4dl .accdb .accdc .accde .accdr .accdt .accft
.adb .ade .adf .adp .arc .ora .alf .ask
.btr .bdf .cat .cdb .ckp .cma .cpd .dacpac
.dad .dadiagrams .daschema .db .db-shm .db-wal .db3 .dbc
.dbf .dbs .dbt .dbv . dbx . dcb . dct . dcx
. ddl . dlis . dp1 . dqy . dsk . dsn . dtsx . dxl
. eco . ecx . edb . epim . exb . fcd . fdb . fic
. fmp . fmp12 . fmpsl . fol .fp3 . fp4 . fp5 . fp7
. fpt . frm . gdb . grdb . gwi . hdb . his . ib
. idb . ihx . itdb . itw . jet . jtx . kdb . kexi
. kexic . kexis . lgc . lwx . maf . maq . mar . masmav
. mdb . mpd . mrg . mud . mwb . myd . ndf . nnt
. nrmlib . ns2 . ns3 . ns4 . nsf . nv . nv2 . nwdb
. nyf . odb . ogy . orx . owc . p96 . p97 . pan
. pdb . pdm . pnz . qry . qvd . rbf . rctd . rod
. rodx . rpd . rsd . sas7bdat . sbf . scx . sdb . sdc
. sdf . sis . spg . sql . sqlite . sqlite3 . sqlitedb . te
. temx . tmd . tps . trc . trm . udb . udl . usr
. v12 . vis . vpd . vvv . wdb . wmdb . wrk . xdb
. xld . xmlff . abcddb . abs . abx . accdw . and . db2
. fm5 . hjt . icg . icr . kdb . lut . maw . mdn
. mdt              

Shared folders targeted for encryption (Example: [IP address]Downloads):

Users Backup Veeam homes home
media common Server Public Web
Images Downloads BackupData ActiveBackupForBusiness Backups
NAS-DC DCBACKUP DirectorFiles share  

File extensions ignored:

.ini .url .msilog .log .ldf .lock .theme .msi
.sys .wpx .cpl .adv .msc .scr .key .ico
.dll .hta .deskthemepack .nomedia .msu .rtp .msp .idx
.ani .386 .diagcfg .bin .mod .ics .com .hlp
 .spl .nls .cab .exe .diagpkg .icl .ocx .rom
.prf .thempack .msstyles .icns .mpa .drv .cur .diagcab
.cmd .shs            

Folders ignored:

windows boot program files (x86) windows.old programdata
intel bitdefender trend micro windowsapps appdata
application data system volume information perflogs msocache  

Files ignored:

bootnxt ntldr bootmgr thumbs.db
ntuser.dat bootsect.bak autoexec.bat iconcache.db

Processes terminated:

teracopy teamviewer nsservice nsctrl uranium
processhacker procmon pestudio procmon64 x32dbg
x64dbg cff explorer procexp pslist tcpview
tcpvcon dbgview rammap rammap64 vmmap
ollydbg autoruns autorunssc filemon regmon
idaq idaq64 immunitydebugger wireshark dumpcap
hookexplorer importrec petools lordpe sysinspector
proc_analyzer sysanalyzer sniff_hit windbg joeboxcontrol
joeboxserver resourcehacker fiddler httpdebugger dumpit
rammap rammap64 vmmap agntsvc cntaosmgr
dbeng50 dbsnmp encsvc infopath isqlplussvc
mbamtray msaccess msftesql mspub mydesktopqos
mydesktopservice mysqld mysqld-nt mysqld-opt Ntrtscan
ocautoupds ocomm ocssd onenote oracle
outlook PccNTMon powerpnt sqbcoreservice sql
sqlagent sqlbrowser sqlservr sqlwriter steam
synctime tbirdconfig thebat thebat64 thunderbird
tmlisten visio winword wordpad xfssvccon

Services terminated:

CybereasonRansomFree vnetd bpcd SamSs TeraCopyService
msftesql nsService klvssbridge64 vapiendpoint ShMonitor
Smcinst SmcService SntpService svcGenericHost Swi_
TmCCSF tmlisten TrueKey TrueKeyScheduler TrueKeyServiceHelper
WRSVC McTaskManager OracleClientCache80 mfefire wbengine
mfemms RESvc mfevtp sacsvr SAVAdminService
SepMasterService PDVFSService ESHASRV SDRSVC FA_Scheduler
KAVFS KAVFS_KAVFSGT kavfsslp klnagent macmnsvc
masvc MBAMService MBEndpointAgent McShield audioendpointbuilder
Antivirus AVP DCAgent bedbg EhttpSrv
MMS ekrn EPSecurityService EPUpdateService ntrtscan
EsgShKernel msexchangeadtopology AcrSch2Svc MSOLAP$TPSAMA Intel(R) PROSet Monitoring
msexchangeimap4 ARSM unistoresvc_1af40a ReportServer$TPS MSOLAP$SYSTEM_BGC
W3Svc MSExchangeSRS ReportServer$TPSAMA Zoolz 2 Service MSOLAP$TPS
aphidmonitorservice SstpSvc MSExchangeMTA ReportServer$SYSTEM_BGC Symantec System
UI0Detect MSExchangeSA MSExchangeIS ReportServer MsDtsServer110
POP3Svc MSExchangeMGMT SMTPSvc MsDtsServer IisAdmin
MSExchangeES EraserSvc11710 Enterprise Client Service MsDtsServer100 NetMsmqActivator
stc_raw_agent VSNAPVSS PDVFSService AcrSch2Svc Acronis
CASAD2DWebSvc CAARCUpdateSvc McAfee avpsus DLPAgentService
mfewc BMR Boot Service DefWatch ccEvtMgr ccSetMgr
SavRoam RTVsc screenconnect ransom sqltelemetry msexch
vnc teamviewer msolap veeam backup
sql memtas vss sophos svc$
mepocs wuauserv      

Drivers that Blackbyte can bypass:

360avflt.sys 360box.sys 360fsflt.sys 360qpesv.sys 5nine.cbt.sys
a2acc.sys a2acc64.sys a2ertpx64.sys a2ertpx86.sys a2gffi64.sys
a2gffx64.sys a2gffx86.sys aaf.sys aalprotect.sys abrpmon.sys
accessvalidator.sys acdriver.sys acdrv.sys adaptivaclientcache32.sys adaptivaclientcache64.sys
adcvcsnt.sys adspiderdoc.sys aefilter.sys agentrtm64.sys agfsmon.sys
agseclock.sys agsyslock.sys ahkamflt.sys ahksvpro.sys ahkusbfw.sys
ahnrghlh.sys aictracedrv_am.sys airship-filter.sys ajfsprot.sys alcapture.sys
alfaff.sys altcbt.sys amfd.sys amfsm.sys amm6460.sys
amm8660.sys amsfilter.sys amznmon.sys antileakfilter.sys antispyfilter.sys
anvfsm.sys apexsqlfilterdriver.sys appcheckd.sys appguard.sys appvmon.sys
arfmonnt.sys arta.sys arwflt.sys asgard.sys ashavscan.sys
asiofms.sys aswfsblk.sys aswmonflt.sys aswsnx.sys aswsp.sys
aszfltnt.sys atamptnt.sys atc.sys atdragent.sys atdragent64.sys
aternityregistryhook.sys atflt.sys atrsdfw.sys auditflt.sys aupdrv.sys
avapsfd.sys avc3.sys avckf.sys avfsmn.sys avgmfi64.sys
avgmfrs.sys avgmfx64.sys avgmfx86.sys avgntflt.sys avgtpx64.sys
avgtpx86.sys avipbb.sys avkmgr.sys avmf.sys awarecore.sys
axfltdrv.sys axfsysmon.sys ayfilter.sys b9kernel.sys backupreader.sys
bamfltr.sys bapfecpt.sys bbfilter.sys bd0003.sys bddevflt.sys
bdfiledefend.sys bdfilespy.sys bdfm.sys bdfsfltr.sys bdprivmon.sys
bdrdfolder.sys bdsdkit.sys bdsfilter.sys bdsflt.sys bdsvm.sys
bdsysmon.sys bedaisy.sys bemk.sys bfaccess.sys bfilter.sys
bfmon.sys bhdrvx64.sys bhdrvx86.sys bhkavka.sys bhkavki.sys
bkavautoflt.sys bkavsdflt.sys blackbirdfsa.sys blackcat.sys bmfsdrv.sys
bmregdrv.sys boscmflt.sys bosfsfltr.sys bouncer.sys boxifier.sys
brcow_x_x_x_x.sys brfilter.sys brnfilelock.sys brnseclock.sys browsermon.sys
bsrfsflt.sys bssaudit.sys bsyaed.sys bsyar.sys bsydf.sys
bsyirmf.sys bsyrtm.sys bsysp.sys bsywl.sys bwfsdrv.sys
bzsenspdrv.sys bzsenth.sys bzsenyaradrv.sys caadflt.sys caavfltr.sys
cancelsafe.sys carbonblackk.sys catflt.sys catmf.sys cbelam.sys
cbfilter20.sys cbfltfs4.sys cbfsfilter2017.sys cbfsfilter2020.sys cbsampledrv.sys
cdo.sys cdrrsflt.sys cdsgfsfilter.sys centrifyfsf.sys cfrmd.sys
cfsfdrv cgwmf.sys change.sys changelog.sys chemometecfilter.sys
ciscoampcefwdriver.sys ciscoampheurdriver.sys ciscosam.sys clumiochangeblockmf.sys cmdccav.sys
cmdcwagt.sys cmdguard.sys cmdmnefs.sys cmflt.sys code42filter.sys
codex.sys conduantfsfltr.sys containermonitor.sys cpavfilter.sys cpavkernel.sys
cpepmon.sys crexecprev.sys crncache32.sys crncache64.sys crnsysm.sys
cruncopy.sys csaam.sys csaav.sys csacentr.sys csaenh.sys
csagent.sys csareg.sys csascr.sys csbfilter.sys csdevicecontrol.sys
csfirmwareanalysis.sys csflt.sys csmon.sys cssdlp.sys ctamflt.sys
ctifile.sys ctinet.sys ctrpamon.sys ctx.sys cvcbt.sys
cvofflineflt32.sys cvofflineflt64.sys cvsflt.sys cwdriver.sys cwmem2k64.sys
cybkerneltracker.sys cylancedrv64.sys cyoptics.sys cyprotectdrv32.sys cyprotectdrv64.sys
cytmon.sys cyverak.sys cyvrfsfd.sys cyvrlpc.sys cyvrmtgn.sys
datanow_driver.sys dattofsf.sys da_ctl.sys dcfafilter.sys dcfsgrd.sys
dcsnaprestore.sys deepinsfs.sys delete_flt.sys devmonminifilter.sys dfmfilter.sys
dgedriver.sys dgfilter.sys dgsafe.sys dhwatchdog.sys diflt.sys
diskactmon.sys dkdrv.sys dkrtwrt.sys dktlfsmf.sys dnafsmonitor.sys
docvmonk.sys docvmonk64.sys dpmfilter.sys drbdlock.sys drivesentryfilterdriver2lite.sys
drsfile.sys drvhookcsmf.sys drvhookcsmf_amd64.sys drwebfwflt.sys drwebfwft.sys
dsark.sys dsdriver.sys dsfemon.sys dsflt.sys dsfltfs.sys
dskmn.sys dtdsel.sys dtpl.sys dwprot.sys dwshield.sys
dwshield64.sys eamonm.sys easeflt.sys easyanticheat.sys eaw.sys
ecatdriver.sys edevmon.sys ednemfsfilter.sys edrdrv.sys edrsensor.sys
edsigk.sys eectrl.sys eetd32.sys eetd64.sys eeyehv.sys
eeyehv64.sys egambit.sys egfilterk.sys egminflt.sys egnfsflt.sys
ehdrv.sys elock2fsctldriver.sys emxdrv2.sys enigmafilemondriver.sys enmon.sys
epdrv.sys epfw.sys epfwwfp.sys epicfilter.sys epklib.sys
epp64.sys epregflt.sys eps.sys epsmn.sys equ8_helper.sys
eraser.sys esensor.sys esprobe.sys estprmon.sys estprp.sys
estregmon.sys estregp.sys estrkmon.sys estrkr.sys eventmon.sys
evmf.sys evscase.sys excfs.sys exprevdriver.sys failattach.sys
failmount.sys fam.sys fangcloud_autolock_driver.sys fapmonitor.sys farflt.sys
farwflt.sys fasdriver fcnotify.sys fcontrol.sys fdrtrace.sys
fekern.sys fencry.sys ffcfilt.sys ffdriver.sys fildds.sys
filefilter.sys fileflt.sys fileguard.sys filehubagent.sys filemon.sys
filemonitor.sys filenamevalidator.sys filescan.sys filesharemon.sys filesightmf.sys
filesystemcbt.sys filetrace.sys file_monitor.sys file_protector.sys file_tracker.sys
filrdriver.sys fim.sys fiometer.sys fiopolicyfilter.sys fjgsdis2.sys
fjseparettifilterredirect.sys flashaccelfs.sys flightrecorder.sys fltrs3
fmdrive.sys fmkkc.sys fmm.sys fortiaptfilter.sys fortimon2.sys
fortirmon.sys fortishield.sys fpav_rtp.sys fpepflt.sys fsafilter.sys
fsatp.sys fsfilter.sys fsgk.sys fshs.sys fsmon.sys
fsmonitor.sys fsnk.sys fsrfilter.sys fstrace.sys fsulgk.sys
fsw31rj1.sys gagsecurity.sys gbpkm.sys gcffilter.sys gddcv.sys
gefcmp.sys gemma.sys geprotection.sys ggc.sys gibepcore.sys
gkff.sys gkff64.sys gkpfcb.sys gkpfcb64.sys gofsmf.sys
gpminifilter.sys groundling32.sys groundling64.sys gtkdrv.sys gumhfilter.sys
gzflt.sys hafsnk.sys hbflt.sys hbfsfltr.sys hcp_kernel_acq.sys
hdcorrelatefdrv.sys hdfilemon.sys hdransomoffdrv.sys hdrfs.sys heimdall.sys
hexisfsmonitor.sys hfileflt.sys hiofs.sys hmpalert.sys hookcentre.sys
hooksys.sys hpreg.sys hsmltmon.sys hsmltwhl.sys hssfwhl.sys
hvlminifilter.sys ibr2fsk.sys iccfileioad.sys iccfilteraudit.sys iccfiltersc.sys
icfclientflt.sys icrlmonitor.sys iderafilterdriver.sys ielcp.sys ieslp.sys
ifs64.sys ignis.sys iguard.sys iiscache.sys ikfilesec.sys
im.sys imffilter.sys imfilter.sys imgguard.sys immflex.sys
immunetprotect.sys immunetselfprotect.sys inisbdrv64.sys ino_fltr.sys intelcas.sys
intmfs.sys inuse.sys invprotectdrv.sys invprotectdrv64.sys ionmonwdrv.sys
iothorfs.sys ipcomfltr.sys ipfilter.sys iprotect.sys iridiumswitch.sys
irongatefd.sys isafekrnl.sys isafekrnlmon.sys isafermon isecureflt.sys
isedrv.sys isfpdrv.sys isirmfmon.sys isregflt.sys isregflt64.sys
issfltr.sys issregistry.sys it2drv.sys it2reg.sys ivappmon.sys
iwdmfs.sys iwhlp.sys iwhlp2.sys iwhlpxp.sys jdppsf.sys
jdppwf.sys jkppob.sys jkppok.sys jkpppf.sys jkppxk.sys
k7sentry.sys kavnsi.sys kawachfsminifilter.sys kc3.sys kconv.sys
kernelagent32.sys kewf.sys kfac.sys kfileflt.sys kisknl.sys
klam.sys klbg.sys klboot.sys kldback.sys kldlinf.sys
kldtool.sys klfdefsf.sys klflt.sys klgse.sys klhk.sys
klif.sys klifaa.sys klifks.sys klifsm.sys klrsps.sys
klsnsr.sys klupd_klif_arkmon.sys kmkuflt.sys kmnwch.sys kmxagent.sys
kmxfile.sys kmxsbx.sys ksfsflt.sys ktfsfilter.sys ktsyncfsflt.sys
kubwksp.sys lafs.sys lbd.sys lbprotect.sys lcgadmon.sys
lcgfile.sys lcgfilemon.sys lcmadmon.sys lcmfile.sys lcmfilemon.sys
lcmprintmon.sys ldsecdrv.sys libwamf.sys livedrivefilter.sys llfilter.sys
lmdriver.sys lnvscenter.sys locksmith.sys lragentmf.sys lrtp.sys
magicbackupmonitor.sys magicprotect.sys majoradvapi.sys marspy.sys maxcryptmon.sys
maxproc64.sys maxprotector.sys mbae64.sys mbam.sys mbamchameleon.sys
mbamshuriken.sys mbamswissarmy.sys mbamwatchdog.sys mblmon.sys mcfilemon32.sys
mcfilemon64.sys mcstrg.sys mearwfltdriver.sys message.sys mfdriver.sys
mfeaack.sys mfeaskm.sys mfeavfk.sys mfeclnrk.sys mfeelamk.sys
mfefirek.sys mfehidk.sys mfencbdc.sys mfencfilter.sys mfencoas.sys
mfencrk.sys mfeplk.sys mfewfpk.sys miniicpt.sys minispy.sys
minitrc.sys mlsaff.sys mmpsy32.sys mmpsy64.sys monsterk.sys
mozycorpfilter.sys mozyenterprisefilter.sys mozyentfilter.sys mozyhomefilter.sys mozynextfilter.sys
mozyoemfilter.sys mozyprofilter.sys mpfilter.sys mpkernel.sys mpksldrv.sys
mpxmon.sys mracdrv.sys mrxgoogle.sys mscan-rt.sys msiodrv4.sys
msixpackagingtoolmonitor.sys msnfsflt.sys mspy.sys mssecflt.sys mtsvcdf.sys
mumdi.sys mwac.sys mwatcher.sys mwfsmfltr.sys mydlpmf.sys
namechanger.sys nanoavmf.sys naswsp.sys ndgdmk.sys neokerbyfilter
netaccctrl.sys netaccctrl64.sys netguard.sys netpeeker.sys ngscan.sys
nlcbhelpi64.sys nlcbhelpx64.sys nlcbhelpx86.sys nlxff.sys nmlhssrv01.sys
nmpfilter.sys nntinfo.sys novashield.sys nowonmf.sys npetw.sys
nprosec.sys npxgd.sys npxgd64.sys nravwka.sys nrcomgrdka.sys
nrcomgrdki.sys nregsec.sys nrpmonka.sys nrpmonki.sys nsminflt.sys
nsminflt64.sys ntest.sys ntfsf.sys ntguard.sys ntps_fa.sys
nullfilter.sys nvcmflt.sys nvmon.sys nwedriver.sys nxfsmon.sys
nxrmflt.sys oadevice.sys oavfm.sys oczminifilter.sys odfsfilter.sys
odfsfimfilter.sys odfstokenfilter.sys offsm.sys omfltlh.sys osiris.sys
ospfile_mini.sys ospmon.sys parity.sys passthrough.sys path8flt.sys
pavdrv.sys pcpifd.sys pctcore.sys pctcore64.sys pdgenfam.sys
pecfilter.sys perfectworldanticheatsys.sys pervac.sys pfkrnl.sys pfracdrv.sys
pgpfs.sys pgpwdefs.sys phantomd.sys phdcbtdrv.sys pkgfilter.sys
pkticpt.sys plgfltr.sys plpoffdrv.sys pointguardvista64f.sys pointguardvistaf.sys
pointguardvistar32.sys pointguardvistar64.sys procmon11.sys proggerdriver.sys psacfileaccessfilter.sys
pscff.sys psgdflt.sys psgfoctrl.sys psinfile.sys psinproc.sys
psisolator.sys pwipf6.sys pwprotect.sys pzdrvxp.sys qdocumentref.sys
qfapflt.sys qfilter.sys qfimdvr.sys qfmon.sys qminspec.sys
qmon.sys qqprotect.sys qqprotectx64.sys qqsysmon.sys qqsysmonx64.sys
qutmdrv.sys ranpodfs.sys ransomdefensexxx.sys ransomdetect.sys reaqtor.sys
redlight.sys regguard.sys reghook.sys regmonex.sys repdrv.sys
repmon.sys revefl
reveprocprotection.sys revonetdriver.sys rflog.sys
rgnt.sys rmdiskmon.sys rmphvmonitor.sys rpwatcher.sys rrmon32.sys
rrmon64.sys rsfdrv.sys rsflt.sys rspcrtw.sys rsrtw.sys
rswctrl.sys rswmon.sys rtologon.sys rtw.sys ruaff.sys
rubrikfileaudit.sys ruidiskfs.sys ruieye.sys ruifileaccess.sys ruimachine.sys
ruiminispy.sys rvsavd.sys rvsmon.sys rw7fsflt.sys rwchangedrv.sys
ryfilter.sys ryguard.sys safe-agent.sys safsfilter.sys sagntflt.sys
sahara.sys sakfile.sys sakmfile.sys samflt.sys samsungrapidfsfltr.sys
sanddriver.sys santa.sys sascan.sys savant.sys savonaccess.sys
scaegis.sys scauthfsflt.sys scauthiodrv.sys scensemon.sys scfltr.sys
scifsflt.sys sciptflt.sys sconnect.sys scred.sys sdactmon.sys
sddrvldr.sys sdvfilter.sys se46filter.sys secdodriver.sys secone_filemon10.sys
secone_proc10.sys secone_reg10.sys secone_usb.sys secrmm.sys secufile.sys
secure_os.sys secure_os_mf.sys securofsd_x64.sys sefo.sys segf.sys
segiraflt.sys segmd.sys segmp.sys sentinelmonitor.sys serdr.sys
serfs.sys sfac.sys sfavflt.sys sfdfilter.sys sfpmonitor.sys
sgresflt.sys shdlpmedia.sys shdlpsf.sys sheedantivirusfilterdriver.sys sheedselfprotection.sys
shldflt.sys si32_file.sys si64_file.sys sieflt.sys simrep.sys
sisipsfilefilter sk.sys skyamdrv.sys skyrgdrv.sys skywpdrv.sys
slb_guard.sys sld.sys smbresilfilter.sys smdrvnt.sys sndacs.sys
snexequota.sys snilog.sys snimg.sys snscore.sys snsrflt.sys
sodatpfl.sys softfilterxxx.sys soidriver.sys solitkm.sys sonar.sys
sophosdt2.sys sophosed.sys sophosntplwf.sys sophossupport.sys spbbcdrv.sys
spellmon.sys spider3g.sys spiderg3.sys spiminifilter.sys spotlight.sys
sprtdrv.sys sqlsafefilterdriver.sys srminifilterdrv.sys srtsp.sys srtsp64.sys
srtspit.sys ssfmonm.sys ssrfsf.sys ssvhook.sys stcvsm.sys
stegoprotect.sys stest.sys stflt.sys stkrnl64.sys storagedrv.sys
strapvista.sys strapvista64.sys svcbt.sys swcommfltr.sys swfsfltr.sys
swfsfltrv2.sys swin.sys symafr.sys symefa.sys symefa64.sys
symefasi.sys symevent.sys symevent64x86.sys symevnt.sys symevnt32.sys
symhsm.sys symrg.sys sysdiag.sys sysmon.sys sysmondrv.sys
sysplant.sys szardrv.sys szdfmdrv.sys szdfmdrv_usb.sys szedrdrv.sys
szpcmdrv.sys taniumrecorderdrv.sys taobserveflt.sys tbfsfilt.sys tbmninifilter.sys
tbrdrv.sys tdevflt.sys tedrdrv.sys tenrsafe2.sys tesmon.sys
tesxnginx.sys tesxporter.sys tffregnt.sys tfsflt.sys tgfsmf.sys
thetta.sys thfilter.sys threatstackfim.sys tkdac2k.sys tkdacxp.sys
tkdacxp64.sys tkfsavxp.sys tkfsavxp64.sys tkfsft.sys tkfsft64.sys
tkpcftcb.sys tkpcftcb64.sys tkpl2k.sys tkpl2k64.sys tksp2k.sys
tkspxp.sys tkspxp64.sys tmactmon.sys tmcomm.sys tmesflt.sys
tmevtmgr.sys tmeyes.sys tmfsdrv2.sys tmkmsnsr.sys tmnciesc.sys
tmpreflt.sys tmumh.sys tmums.sys tmusa.sys tmxpflt.sys
topdogfsfilt.sys trace.sys trfsfilter.sys tritiumfltr.sys trpmnflt.sys
trufos.sys trustededgeffd.sys tsifilemon.sys tss.sys tstfilter.sys
tstfsredir.sys tstregredir.sys tsyscare.sys tvdriver.sys tvfiltr.sys
tvmfltr.sys tvptfile.sys tvspfltr.sys twbdcfilter.sys txfilefilter.sys
txregmon.sys uamflt.sys ucafltdriver.sys ufdfilter.sys uncheater.sys
upguardrealtime.sys usbl_ifsfltr.sys usbpdh.sys usbtest.sys uvmcifsf.sys
uwfreg.sys uwfs.sys v3flt2k.sys v3flu2k.sys v3ift2k.sys
v3iftmnt.sys v3mifint.sys varpffmon.sys vast.sys vcdriv.sys
vchle.sys vcmfilter.sys vcreg.sys veeamfct.sys vfdrv.sys
vfilefilter.sys vfpd.sys vfsenc.sys vhddelta.sys vhdtrack.sys
vidderfs.sys vintmfs.sys virtfile.sys virtualagent.sys vk_fsf.sys
vlflt.sys vmwvvpfsd.sys vollock.sys vpdrvnt.sys vradfil2.sys
vraptdef.sys vraptflt.sys vrarnflt.sys vrbbdflt.sys vrexpdrv.sys
vrfsftm.sys vrfsftmx.sys vrnsfilter.sys vrsdam.sys vrsdcore.sys
vrsdetri.sys vrsdetrix.sys vrsdfmx.sys vrvbrfsfilter.sys vsepflt.sys
vsscanner.sys vtsysflt.sys vxfsrep.sys wats_se.sys wbfilter.sys
wcsdriver.sys wdcfilter.sys wdfilter.sys wdocsafe.sys wfp_mrt.sys
wgfile.sys whiteshield.sys windbdrv.sys windd.sys winfladrv.sys
winflahdrv.sys winfldrv.sys winfpdrv.sys winload.sys winteonminifilter.sys
wiper.sys wlminisecmod.sys wntgpdrv.sys wraekernel.sys wrcore.sys
wrcore.x64.sys wrdwizfileprot.sys wrdwizregprot.sys wrdwizscanner.sys wrdwizsecure64.sys
wrkrn.sys wrpfv.sys wsafefilter.sys wscm.sys xcpl.sys
xendowflt.sys xfsgk.sys xhunter1.sys xhunter64.sys xiaobaifs.sys
xiaobaifsr.sys xkfsfd.sys xoiv8x64.sys xomfcbt8x64.sys yahoostorage.sys
yfsd.sys yfsd2.sys yfsdr.sys yfsrd.sys zampit_ml.sys
zesfsmf.sys zqfilter.sys zsfprt.sys zwasatom.sys zwpxesvr.sys
zxfsfilt.sys zyfm.sys zzpensys.sys    

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This article was originally published by Microsoft's Windows Security Blog. You can find the original article here.