BKDR_NEUREVT.TTX

January 21, 2015
 Analysis by: Michael John Marcos
 ALIASES:

Trojan:Win32/Neurevt.C (Microsoft), a variant of Win32/Injector.BLXX (Eset), Mal/Wonton-J (Sophos)

 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: Backdoor

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Downloaded from the Internet, Dropped by other malware

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.

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 deletes the initially executed copy of itself.

  TECHNICAL DETAILS

File Size:

379,904 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

18 Dec 2014

Payload:

Connects to URLs/IPs, Compromises system security

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 drops the following files:

  • %User Profile%\My Documents\My Videos\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.)

It drops the following copies of itself into the affected system:

  • %Program Data%\Common Files\CreativeAudio\{random value}.exe

It adds the following processes:

  • explorer.exe

It creates the following folders:

  • %Program Data%\Common Files\CreativeAudio
  • %User Profile%\My Documents\My Videos

(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.)

It stays memory-resident by injecting codes into the following processes:

  • created explorer.exe

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
CreativeAudio = %ProgramData%\CreativeAudio\{random value}.exe

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Run
CreativeAudio = %ProgramData%\CreativeAudio\{random value}.exe

Other System Modifications

This backdoor adds the following registry keys:

HKEY_CURRENT_USER\Software
Win7zip =

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows NT\CurrentVersion\Image File Execution Options\
{malware name}.exe
DisableExceptionChainValidation =

It adds the following registry entries:

HKEY_LOCAL_MACHINE\­SOFTWARE\­Microsoft\
­Windows\­CurrentVersion\­Policies\
­Explorer
TaskbarNoNotification = 1

HKEY_LOCAL_MACHINE\­SOFTWARE\­Microsoft\
­Windows\­CurrentVersion\­Policies\
­Explorer
HideSCAHealth = 1

HKEY_LOCAL_MACHINE\­SOFTWARE\­Microsoft\
­Windows\­CurrentVersion\­WindowsBackup
DisableMonitoring = 1

HKEY_LOCAL_MACHINE\­SOFTWARE\­JavaSoft\
­Java Plug-in\­{version}
UseJava2IExplorer = 0

HKEY_CURRENT_USER\­SOFTWARE\­Adobe\
­Acrobat Reader\­{version}\­Privileged
bProtectedMode = 1

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

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

Backdoor Routine

This backdoor 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:

  • http://{BLOCKED}.{BLOCKED}earevideos1k1.com/direct/mail/order.php?id={random value}
  • http://{BLOCKED}.{BLOCKED}earevideos2k2.com/direct/mail/order.php?id={random value}
  • http://{BLOCKED}.{BLOCKED}teasemek3.com/direct/mail/order.php?id={random value}
  • http://{BLOCKED}.{BLOCKED}tzonek4.com/direct/mail/order.php?id={random value}
  • http://{BLOCKED}.{BLOCKED}ydartk5.com/direct/mail/order.php?id={random value}
  • http://{BLOCKED}.{BLOCKED}wipemek6.com/direct/mail/order.php?id={random value}
  • http://{BLOCKED}.{BLOCKED}mejuststarted11k7.com/direct/mail/order.php?id={random value}
  • http://{BLOCKED}.{BLOCKED}mejuststarted13k8.com/direct/mail/order.php?id={random value}
  • http://{BLOCKED}.{BLOCKED}mejuststarted14k9.com/direct/mail/order.php?id={random value}
  • http://{BLOCKED}.{BLOCKED}amejuststarted15k10.com/direct/mail/order.php?id={random value}
  • http://{BLOCKED}.{BLOCKED}amejuststarted12k11.com/direct/mail/order.php?id={random value}
  • http://{BLOCKED}.{BLOCKED}amejuststarted10k12.com/direct/mail/order.php?id={random value}
  • http://{BLOCKED}.{BLOCKED}wkwefewaaaaa3.com/direct/mail/order.php?id={random value}
  • http://BLOCKED}.{BLOCKED}wkwefewaaaaa4.com/direct/mail/order.php?id={random value}
  • http://{BLOCKED}.{BLOCKED}wkwefewaaaaa5.com/direct/mail/order.php?id={random value}
  • http://{BLOCKED}.{BLOCKED}wkwefewaaaaa6.com/direct/mail/order.php?id={random value}

Web Browser Home Page and Search Page Modification

This backdoor modifies the Internet Explorer Zone Settings.

Information Theft

This backdoor gathers the following data:

  • System Information
  • Java version
  • Remote Desktop records
  • UAC enabled (Y/N)
  • Has Battery (Y/N)
  • locally stored FTP credentials
  • .NET version
  • Installed messaging software (Skype)
  • Installed anti-malware products (Symantec, AVP, AVG, Avira, ESET, McAfee, Trend Micro, Avast, Microsoft Security Client, Bitdefender, BullGuard, Rising, Arcabit, Webroot, Emsisoft, F-Secure, Panda and etc.)
  • Installed browser
  • Operating system version
  • Installed software (Minecraft, Runescape, League of Legends, VMWare, Visual Studio, Blizzard Entertainment, Valve, .Net Framework, Java, Steam, SysInternals tools, mIRC, Hex-Rays, Immunity Inc., CodeBlocks, 7-Zip, PrestoSoft, Nmap, Perl, Visual Studio and Wireshark)

Other Details

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

  • http://update.microsoft.com
  • http://microsoft.com
  • http://windowsupdate.microsoft.com

It deletes the initially executed copy of itself

NOTES:
This backdoor disables the following services:

  • wuauserv
  • wscsvc
  • BITS
  • MpsSvc
  • SharedAccess

It creates the following registry to lower security settings:

HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\1
2500 = 3

HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\2
2500 = 3

HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\3
2500 = 3

HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\4
2500 = 3

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

Where {application} are as follows:

  • a2guard.exe
  • a2service.exe
  • a2start.exe
  • adaware.exe
  • ALUpdate.exe
  • arcaclean.exe
  • avastsvc.exe
  • avastui.exe
  • avcenter.exe
  • AVENGINE.exe
  • avgcfgex.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
  • drstrui.exe
  • egui.exe
  • ekrn.exe
  • epavjobs.exe
  • ForceField.exe
  • FProtTray.exe
  • FPWin.exe
  • fshoster32.exe
  • GDFirewallTray.exe
  • GDSC.exe
  • hijackthis.exe
  • housecalllauncher.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
  • spybotsd.exe
  • starter_avp.exe
  • symerr.exe
  • uiSeAgnt.exe
  • uiUpdateTray.exe
  • uiWatchDog.exe
  • Update.exe
  • update_tmp.exe
  • updater.exe
  • Upgrader.exe
  • usrreq.exe
  • uWinMgr.exe
  • WRSA.exe
  • zatray.exe

This backdoor hooks APIs to monitors the activities of the following browsers:

  • firefox.exe
  • tbb-firefox.exe
  • iexplore.exe
  • chrome.exe

  SOLUTION

Minimum Scan Engine:

9.700

FIRST VSAPI PATTERN FILE:

11.354.02

FIRST VSAPI PATTERN DATE:

18 Dec 2014

VSAPI OPR PATTERN File:

11.355.00

VSAPI OPR PATTERN Date:

19 Dec 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

Restart in Safe Mode

[ Learn More ]

Step 3

Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

Step 4

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.

  • HKEY_CURRENT_USER\Software\Win7zip
  • HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\{malware name}.exe\DisableExceptionChainValidation

Step 5

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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • CreativeAudio = %ProgramData%\CreativeAudio\{random value}.exe
  • In HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
    • CreativeAudio = %ProgramData%\CreativeAudio\{random value}.exe
  • In HKEY_LOCAL_MACHINE\­SOFTWARE\­Microsoft\Windows\­CurrentVersion\­Policies\Explorer
    • TaskbarNoNotification = 1
  • In HKEY_LOCAL_MACHINE\­SOFTWARE\­Microsoft\Windows\­CurrentVersion\­Policies\Explorer
    • HideSCAHealth = 1
  • In HKEY_LOCAL_MACHINE\­SOFTWARE\­Microsoft\Windows\­CurrentVersion\­WindowsBackup
    • DisableMonitoring = 1
  • In HKEY_LOCAL_MACHINE\­SOFTWARE\­JavaSoft\Java Plug-in\­{version}
    • UseJava2IExplorer = 0
  • In HKEY_CURRENT_USER\­SOFTWARE\­Adobe\Acrobat Reader\­{version}\­Privileged
    • bProtectedMode = 1
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
    • %Windows%\explorer.exe = "%Windows%\explorer.exe:*:Enabled"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\1
    • 2500 = 3
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\2
    • 2500 = 3
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\3
    • 2500 = 3
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\4
    • 2500 = 3

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.
  • %Program Data%\Common Files\CreativeAudio\{random value}.exe

Step 7

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 Data%\Common Files\CreativeAudio

Step 8

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


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