Trojan.MSIL.REMCOS.USXVPL519
Trojan:Win32/Ursnif.PVK!MTB (Microsoft); RDN/Generic.grp (McAfee); Backdoor.MSIL.NanoBot.aynk (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt)
Windows
Threat Type: Trojan
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
TECHNICAL DETAILS
Arrival Details
This Trojan 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 Trojan adds the following processes:
- %Windows%\Microsoft.NET\Framework\v4.0.30319\RegAsm.exe "{malware file path and name}"
- "schtasks.exe" /create /f /tn "DSL Subsystem" /xml "%User Temp%\tmpE59D.tmp"
(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.. %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 creates the following folders:
- %Application Data%\0EFADD19-2A94-41FB-8931-F2BBC5D61333
- %Application Data%\0EFADD19-2A94-41FB-8931-F2BBC5D61333\Logs\{username}
- %Application Data%\0EFADD19-2A94-41FB-8931-F2BBC5D61333\Logs
(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).)
Autostart Technique
This Trojan drops the following file(s) in the Windows User Startup folder to enable its automatic execution at every system startup:
- %User Startup%\uyyu.exe.vbs
(Note: %User Startup% is the current user's Startup folder, which is usually C:\Windows\Profiles\{user name}\Start Menu\Programs\Startup on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu\Programs\Startup on Windows NT, C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows 2003(32-bit), XP and 2000(32-bit), or C:\Users\{user name}\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit), 10(64-bit).)
Other System Modifications
This Trojan deletes the following files:
- %Windows%\Tasks\DSL Subsystem.job
(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.)
Dropping Routine
This Trojan drops the following files:
- %Application Data%\0EFADD19-2A94-41FB-8931-F2BBC5D61333\task.dat
- %All Users Profile%\Microsoft\Network\Downloader\qmgr1.dat
- %Application Data%\ytge\uyyu.exe.exe
- %All Users Profile%\Microsoft\Network\Downloader\qmgr0.dat
- %Application Data%\0EFADD19-2A94-41FB-8931-F2BBC5D61333\run.dat
(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).. %All Users Profile% is the common user's profile folder, which is usually C:\Documents and Settings\All Users on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\ProgramData on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit). )
Other Details
This Trojan connects to the following possibly malicious URL:
- http://mrfelly.{BLOCKED}s.net
This report is generated via an automated analysis system.
SOLUTION
Step 1
Before doing any scans, Windows 7, Windows 8, Windows 8.1, and Windows 10 users must disable System Restore to allow full scanning of their computers.
Step 2
Restart in Safe Mode
Step 3
Identify and terminate files detected as Trojan.MSIL.REMCOS.USXVPL519
- Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
- If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
- If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.
Step 4
Search and delete these components
- %Application Data%\0EFADD19-2A94-41FB-8931-F2BBC5D61333\task.dat
- %All Users Profile%\Microsoft\Network\Downloader\qmgr1.dat
- %Application Data%\ytge\uyyu.exe.exe
- %All Users Profile%\Microsoft\Network\Downloader\qmgr0.dat
- %Application Data%\0EFADD19-2A94-41FB-8931-F2BBC5D61333\run.dat
Step 5
Search and delete these folders
- %Application Data%\0EFADD19-2A94-41FB-8931-F2BBC5D61333
- %Application Data%\0EFADD19-2A94-41FB-8931-F2BBC5D61333\Logs\{username}
- %Application Data%\0EFADD19-2A94-41FB-8931-F2BBC5D61333\Logs
Step 6
Restart in normal mode and scan your computer with your Trend Micro product for files detected as Trojan.MSIL.REMCOS.USXVPL519. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check this Knowledge Base page for more information.
Step 7
Restore this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.
- %Windows%\Tasks\DSL Subsystem.job
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