BKDR_NEUREVT.MA

 Analysis by: Jimelle Monteser

 ALIASES:

Trojan:AutoIt/Neurevt.A (Microsoft), Win32/Neurevt.B trojan (NOD32)

 PLATFORM:

Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Downloaded from the Internet, Dropped by other malware


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.

It executes commands from a remote malicious user, effectively compromising the affected system. It connects to a website to send and receive information.

It modifies the Internet Explorer Zone Settings.

It retrieves specific information from the affected system.

  TECHNICAL DETAILS

File Size:

471,591 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

12 Mar 2014

Payload:

Compromises system security, Connects to URLs/IPs, Drops files

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 drops the following copies of itself into the affected system:

  • %Program Files%\Common Files\m9dt734hfbjh\{random}.exe

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).)

It creates the following folders:

  • %Program Files%\Common Files\m9dt734hfbjh

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).)

It injects codes into the following process(es):

  • explorer.exe

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
tyc4h08hcv34 = "%Program Files%\Common Files\m9dt734hfbjh\{random}.exe"

HKEY_CURRENT_USER\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
tyc4h08hcv34 = "%Program Files%\Common Files\m9dt734hfbjh\{random}.exe"

Other System Modifications

This Trojan adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Win7zip
Uuid = "{random values}"

It creates the following registry entry(ies) to bypass Windows Firewall:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
%Windows%\explorer.exe = "%Windows%\explorer.exe:*:Enabled"

Backdoor Routine

This Trojan executes the following commands from a remote malicious user:

  • Download and execute files
  • Perform Slowloris flooding
  • Execute shell commands
  • Copy itself in removable drives
  • Open a URL
  • Uninstall / Update itself

It connects to the following websites to send and receive information:

  • {BLOCKED}m.com
  • {BLOCKED}e-silo.com
  • {BLOCKED}ool.info
  • {BLOCKED}ams.com

Web Browser Home Page and Search Page Modification

This Trojan modifies the Internet Explorer Zone Settings.

Dropping Routine

This Trojan drops the following files:

  • %User Profile%\My Documents\My Videos\Desktop.ini
  • %Program Files%\Common Files\m9dt734hfbjh\desktop.ini

(Note: %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.. %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).)

Information Theft

This Trojan retrieves the following information from the affected system:

  • Operating system version
  • Hardware Information (Power Status, Processor)
  • Installed FTP Softwares (CoreFTP,FileZilla,FlashFXP,FTP Commander,PuTTy,SmartFTP,WinSCP)
  • Installed Game Softwares (Steam, League of Legends,Origin, Blizzard, Origin, Runescape)
  • Installed Messenger (Skype)
  • Installed AV Products
  • Username
  • Default Browser
  • Dotnet Version
  • Java Version
  • IPs of recent RDP
  • Installed Softwares (Sysinternals, mIRC, Hex-Rays, Immunity Inc, CodeBlocks,7-Zip,PrestoSoft,Nmap,Perl,Visual C++, Wireshark, Visual Studio, VMWare, Inc.)

Other Details

This Trojan connects to the following URL(s) to check for an Internet connection:

  • update.microsoft.com
  • microsoft.com
  • windowsupdate.microsoft.com

NOTES:

It queries the following registry key to get Microsoft Net Framework Version:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Net Framework setup\NDP

It queries the following registry key to get the processor information:

HKEY_LOCAL_MACHINE\HARDWARE\DESCRIPTION\System\CentralProcessor

It disables the following antivirus-related applications by adding the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\ Windows NT\CurrentVersion\Image File Execution Options\{application} Debugger = "{random characters}_.exe"

{random characters} can be any of the following:

  • a2guard.exe
  • a2service.exe
  • a2start.exe
  • adaware.exe
  • ALUpdate.exe
  • arcaclean.exe
  • avastsvc.exe
  • avastui.exe
  • avcenter.exe
  • AVENGINE.exe
  • avgcfgex.exe
  • avgdiagex.exe
  • avgidsagent.exe
  • avgmfapx.exe
  • avgnt.exe
  • avguard.exe
  • avgui.exe
  • avgupd.exe
  • avgwdsvc.exe
  • AVK.exe
  • AVKTray.exe
  • avshadow.exe
  • BgScan.exe
  • BullGuard.exe
  • BullGuardBhvScanner.exe
  • BullGuardScanner.exe
  • BullGuardUpdate.exe
  • BullGuardUpdate2.exe
  • ccsvchst.exe
  • ccupdate.exe
  • CLPSLA.exe
  • coreFrameworkHost.exe
  • coreServiceShell.exe
  • egui.exe
  • ekrn.exe
  • epavjobs.exe
  • ForceField.exe
  • FProtTray.exe
  • FPWin.exe
  • fshoster32.exe
  • GDFirewallTray.exe
  • GDSC.exe
  • K7TSUpdT.exe
  • mbam.exe
  • mbamgui.exe
  • mcagent.exe
  • McPvTray.exe
  • mcshell.exe
  • mcshield.exe
  • McSvHost.exe
  • McUICnt.exe
  • mcupdate.exe
  • mcupdmgr.exe
  • MSASCui.exe
  • MsMpEng.exe
  • msseces.exe
  • niu.exe
  • op_mon.exe
  • pctsAuxs.exe
  • pctsGui.exe
  • pctsSvc.exe
  • PSANHost.exe
  • PSUAService.exe
  • PSUNMain.exe
  • RavMonD.exe
  • rcfp.exe
  • rsmain.exe
  • RsMgrSvc.exe
  • RsTray.exe
  • SBAMTray.exe
  • sbamui.exe
  • sguardxup.exe
  • starter_avp.exe
  • symerr.exe
  • uiSeAgnt.exe
  • uiWatchDog.exe
  • Update.exe
  • update_tmp.exe
  • updater.exe
  • Upgrader.exe
  • usrreq.exe
  • uWinMgr.exe
  • WRSA.exe
  • zatray.exe

  SOLUTION

Minimum Scan Engine:

9.700

FIRST VSAPI PATTERN FILE:

10.666.05

FIRST VSAPI PATTERN DATE:

15 Mar 2014

VSAPI OPR PATTERN File:

10.667.00

VSAPI OPR PATTERN Date:

16 Mar 2014

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

Scan your computer with your Trend Micro product and note files detected as BKDR_NEUREVT.MA

Step 3

Restart in Safe Mode

[ Learn More ]

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
    • tyc4h08hcv34 = "%Program Files%\Common Files\m9dt734hfbjh\{random}.exe"
  • In HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • tyc4h08hcv34 = "%Program Files%\Common Files\m9dt734hfbjh\{random}.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Win7zip
    • Uuid = "{random values}"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
    • %Windows%\explorer.exe = "%Windows%\explorer.exe:*:Enabled"

Step 5

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.
  • %Program Files%\Common Files\m9dt734hfbjh

Step 6

Search and delete this file

[ Learn More ]
There may be some files 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 Profile%\My Documents\My Videos\Desktop.ini
  • %Program Files%\Common Files\m9dt734hfbjh\desktop.ini

Step 7

Reset Internet security settings

[ Learn More ]

Step 8

Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_NEUREVT.MA. 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.


Did this description help? Tell us how we did.