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TROJ_NEDSYM.YXW

January 10, 2015
 ALIASES:

Trojan:Win32/Nedsym.F, Trojan:Win32/Hider.G (Microsoft); Trojan-Spy.Win32.Zbot.aodm (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt); Trojan horse SHeur3.AZQU (AVG)

 PLATFORM:

Windows

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:

  • 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

File Size:

3,037,696 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

10 Jan 2015

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 creates the following folders:

  • %System Root%\virus
  • %System Root%\RavBin
  • %Start Menu%\Programs\T-Saver
  • %Program Files%\TSaverClient
  • %System Root%\DOCUME~1
  • %System Root%\DOCUME~1\Wilbert
  • %User Profile%\LOCALS~1
  • %User Temp%\nsm3B.tmp
  • %User Profile%\Documents\TSaverClient
  • %User Profile%\TSaverClient\LOG
  • %User Profile%\TSaverClient\pol

(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.. %Start Menu% is the Start Menu folder, where it usually is C:\Documents and Settings\{user name}\Start Menu on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming\Microsoft\Windows\Start Menu on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.. %Program Files% is the Program Files folder, where it usually is C:\Program Files on all Windows operating system versions; C:\Program Files (x86) for 32-bit applications running on Windows 64-bit operating systems.. %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.. %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

Autostart Technique

This Trojan adds the following registry entries to enable its automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
RegistryMonitor1 = "%System%\qtplugin.exe"

Other System Modifications

This Trojan deletes the following files:

  • %System Root%\RavBin\1.bat
  • %User Temp%\nsf20.tmp
  • %User Temp%\nsm3B.tmp

(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.. %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

It adds the following registry keys:

HKEY_CURRENT_USER\Software\WinRAR SFX

HKEY_LOCAL_MACHINE\Software\LiTech\
TSaverClient

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Setup
RegistryMonitor2 = "90359743"

HKEY_CURRENT_USER\Software\WinRAR SFX
C%%RavBin = "%System Root%\RavBin"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
%Program Files%\TSaverClient\TSaverSrv.exe = "{random characters}"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\SharedAccess\Parameters\
FirewallPolicy\DomainProfile\AuthorizedApplications\
List
%Program Files%\TSaverClient\TSaverSrv.exe = "{random characters}"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\GloballyOpenPorts\
List
5945:TCP = "5945:TCP:*:Enabled:TSaverPrint"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\SharedAccess\Parameters\
FirewallPolicy\DomainProfile\GloballyOpenPorts\
List
5945:TCP = "5945:TCP:*:Enabled:TSaverPrint"

HKEY_LOCAL_MACHINE\SOFTWARE\LiTech\
TSaverClient
PATH = "%Program Files%\TSaverClient"

HKEY_LOCAL_MACHINE\SOFTWARE\LiTech\
TSaverClient
PORT = "1739"

HKEY_LOCAL_MACHINE\SOFTWARE\LiTech\
TSaverClient
WEB = "276"

HKEY_LOCAL_MACHINE\SOFTWARE\LiTech\
TSaverClient
SER_IP = "10.91.31.26"

HKEY_LOCAL_MACHINE\SOFTWARE\LiTech\
TSaverClient
SN = "0.0.0.0"

HKEY_LOCAL_MACHINE\SOFTWARE\LiTech\
TSaverClient
VER_CUR = "96"

HKEY_LOCAL_MACHINE\SOFTWARE\LiTech\
TSaverClient
VER_NEW = "96"

HKEY_LOCAL_MACHINE\SOFTWARE\LiTech\
TSaverClient
VER_POL = "0"

HKEY_LOCAL_MACHINE\SOFTWARE\LiTech\
TSaverClient
CNT_APPL = "0"

HKEY_LOCAL_MACHINE\SOFTWARE\LiTech\
TSaverClient
CNT_PRNT = "0"

HKEY_LOCAL_MACHINE\SOFTWARE\LiTech\
TSaverClient
CNT_PROF = "0"

HKEY_LOCAL_MACHINE\SOFTWARE\LiTech\
TSaverClient
ESAVERON = "1"

Dropping Routine

This Trojan drops the following files:

  • %User Temp%\aut2.tmp
  • %User Temp%\aut7.tmp
  • %User Temp%\a.exe
  • %User Temp%\b.exe
  • %User Temp%\c.exe
  • %User Temp%\d.exe
  • __tmp_rar_sfx_access_check_70859
  • hosts
  • 1.bat
  • 1.vbs
  • %User Temp%\nsf22.tmp
  • %Start Menu%\Programs\T-Saver\T-Saver Settings.lnk
  • %Start Menu%\Programs\T-Saver\T-Saver Uninstall.lnk
  • %Program Files%\TSaverClient\TSaverHK.dll
  • %Program Files%\TSaverClient\TSaverAuth.dll
  • %Program Files%\TSaverClient\TSaverSrv.exe
  • %Program Files%\TSaverClient\GateTs.exe
  • %Program Files%\TSaverClient\TSaverService.exe
  • %Program Files%\TSaverClient\TSaverGetCert.exe
  • %Program Files%\TSaverClient\TCPLIBT.dll
  • %Program Files%\TSaverClient\TSaverUtil.dll
  • %Program Files%\TSaverClient\HTTPDownLoad.exe
  • %Program Files%\TSaverClient\remotecall.html
  • %Program Files%\TSaverClient\remotecall_e.html
  • %Program Files%\TSaverClient\tsaver.png
  • %Program Files%\TSaverClient\secucrpr.dll
  • %Program Files%\TSaverClient\ReallyShDn.exe
  • %Program Files%\TSaverClient\TSaverDel.exe
  • %Program Files%\TSaverClient\TSaverGetCert.dll
  • %Program Files%\TSaverClient\TSaverProferty.exe
  • %Program Files%\TSaverClient\TSaverLog.exe
  • %Program Files%\TSaverClient\PowMan.exe
  • %User Temp%\nsm3B.tmp\RegServiceDLL.dll
  • %System Root%\virus\a.exe
  • %System Root%\virus\b.exe

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.. %Start Menu% is the Start Menu folder, where it usually is C:\Documents and Settings\{user name}\Start Menu on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming\Microsoft\Windows\Start Menu on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.. %Program Files% is the Program Files folder, where it usually is C:\Program Files on all Windows operating system versions; C:\Program Files (x86) for 32-bit applications running on Windows 64-bit operating systems.. %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.)

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://{BLOCKED}6.246.90/a.exe
  • http://{BLOCKED}6.246.90/b.exe
  • http://{BLOCKED}6.246.90/c.exe
  • http://{BLOCKED}6.246.90/d.exe
  • {BLOCKED}.244.145
  • {BLOCKED}.115.189
  • {BLOCKED}.172.28
  • {BLOCKED}.54.237

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.700

Step 1

Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.

Step 2

Restart in Safe Mode

[ Learn More ]

Step 3

Delete this registry key

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

  • In HKEY_CURRENT_USER\Software
    • WinRAR SFX
  • In HKEY_LOCAL_MACHINE\Software\LiTech
    • TSaverClient

Step 4

Delete this registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • RegistryMonitor1 = "%System%\qtplugin.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Setup
    • RegistryMonitor2 = "90359743"
  • In HKEY_CURRENT_USER\Software\WinRAR SFX
    • C%%RavBin = "%System Root%\RavBin"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
    • %Program Files%\TSaverClient\TSaverSrv.exe = "{random characters}"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\SharedAccess\Parameters\FirewallPolicy\DomainProfile\AuthorizedApplications\List
    • %Program Files%\TSaverClient\TSaverSrv.exe = "{random characters}"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\GloballyOpenPorts\List
    • 5945:TCP = "5945:TCP:*:Enabled:TSaverPrint"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\SharedAccess\Parameters\FirewallPolicy\DomainProfile\GloballyOpenPorts\List
    • 5945:TCP = "5945:TCP:*:Enabled:TSaverPrint"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\LiTech\TSaverClient
    • PATH = "%Program Files%\TSaverClient"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\LiTech\TSaverClient
    • PORT = "1739"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\LiTech\TSaverClient
    • WEB = "276"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\LiTech\TSaverClient
    • SER_IP = "10.91.31.26"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\LiTech\TSaverClient
    • SN = "0.0.0.0"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\LiTech\TSaverClient
    • VER_CUR = "96"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\LiTech\TSaverClient
    • VER_NEW = "96"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\LiTech\TSaverClient
    • VER_POL = "0"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\LiTech\TSaverClient
    • CNT_APPL = "0"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\LiTech\TSaverClient
    • CNT_PRNT = "0"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\LiTech\TSaverClient
    • CNT_PROF = "0"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\LiTech\TSaverClient
    • ESAVERON = "1"

Step 5

Search and delete these components

[ Learn More ]
There may be some components that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the "More advanced options" option to include all hidden files and folders in the search result.
  • %User Temp%\aut2.tmp
  • %User Temp%\aut7.tmp
  • %User Temp%\a.exe
  • %User Temp%\b.exe
  • %User Temp%\c.exe
  • %User Temp%\d.exe
  • __tmp_rar_sfx_access_check_70859
  • hosts
  • 1.bat
  • 1.vbs
  • %User Temp%\nsf22.tmp
  • %Start Menu%\Programs\T-Saver\T-Saver Settings.lnk
  • %Start Menu%\Programs\T-Saver\T-Saver Uninstall.lnk
  • %Program Files%\TSaverClient\TSaverHK.dll
  • %Program Files%\TSaverClient\TSaverAuth.dll
  • %Program Files%\TSaverClient\TSaverSrv.exe
  • %Program Files%\TSaverClient\GateTs.exe
  • %Program Files%\TSaverClient\TSaverService.exe
  • %Program Files%\TSaverClient\TSaverGetCert.exe
  • %Program Files%\TSaverClient\TCPLIBT.dll
  • %Program Files%\TSaverClient\TSaverUtil.dll
  • %Program Files%\TSaverClient\HTTPDownLoad.exe
  • %Program Files%\TSaverClient\remotecall.html
  • %Program Files%\TSaverClient\remotecall_e.html
  • %Program Files%\TSaverClient\tsaver.png
  • %Program Files%\TSaverClient\secucrpr.dll
  • %Program Files%\TSaverClient\ReallyShDn.exe
  • %Program Files%\TSaverClient\TSaverDel.exe
  • %Program Files%\TSaverClient\TSaverGetCert.dll
  • %Program Files%\TSaverClient\TSaverProferty.exe
  • %Program Files%\TSaverClient\TSaverLog.exe
  • %Program Files%\TSaverClient\PowMan.exe
  • %User Temp%\nsm3B.tmp\RegServiceDLL.dll
  • %System Root%\virus\a.exe
  • %System Root%\virus\b.exe

Step 6

Search and delete these folders

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • %System Root%\virus
  • %System Root%\RavBin
  • %Start Menu%\Programs\T-Saver
  • %Program Files%\TSaverClient
  • %System Root%\DOCUME~1
  • %System Root%\DOCUME~1\Wilbert
  • %User Profile%\LOCALS~1
  • %User Temp%\nsm3B.tmp
  • %User Profile%\Documents\TSaverClient
  • %User Profile%\TSaverClient\LOG
  • %User Profile%\TSaverClient\pol

Step 7

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_NEDSYM.YXW. 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 8

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.

  • %System Root%\RavBin\1.bat
  • %User Temp%\nsf20.tmp
  • %User Temp%\nsm3B.tmp


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