Backdoor.Win32.QUASAR.C

This Backdoor arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Arrival Details

This Backdoor arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Installation

This Backdoor adds the following processes:

• powershell -inputformat none -outputformat none -NonInteractive -Command Add-MpPreference -ExclusionPath "%System Root%\Users"
• schtasks /create /sc minute /mo 5 /tn "Microsoft\SubDir\Subfile" /tr "%Application Data%\SubDir\Subfile.exe" /RL HIGHEST /f
• %Application Data%\Loader.exe %Application Data%\Loader.exe -pP@$$W0RD#@
• timeout 7
• attrib +s +h %Application Data%\SubDir
• attrib +s +h %Application Data%\logs
• attrib +s +h /d /s
• %System%\svchost.exe -k netsvcs
• chcp 65001
• %System%\PING.EXE ping -n 10 localhost
• %Application Data%\Loader.exe

(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.. %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).. %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

Other System Modifications

This Backdoor deletes the following files:

• %User Temp%\A11E.tmp\A12F.tmp\extd.exe

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

It deletes the following folders:

• %User Temp%\A11E.tmp\A12F.tmp

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

Dropping Routine

This Backdoor drops the following files:

• %Application Data%\Loader.exe

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

This report is generated via an automated analysis system.