BKDR_ANDROM.JN

 Analysis by: Jennifer Gumban
 Modified by: Andrei Castillo

 ALIASES:

Troj/VB-GQT(Sophos lite), Trojan horse VB2.YHI(AVG), W32/Kryptik.BJGB!tr(Fortinet), W32/Gamarue.E (exact)(Fprot), Trojan.Gamarue(Ikarus), Trojan-Spy.Win32.Zbot.ntnl(Kaspersky), Worm:Win32/Gamarue.AC(Microsoft), Win32/TrojanDownloader.Wauchos.K trojan(NOD32), Trojan.GenericKD.1135767(BitDefender)

 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 deletes the initially executed copy of itself.

  TECHNICAL DETAILS

Ports:

TCP port 8000 (iRDMI)

File Size:

163,840 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

25 Jul 2013

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 copies of itself into the affected system:

  • %All Users Profile%\{random file name}.exe
  • %All Users Profile%\svchost.exe - for operating systems running on virtual machine
  • %ProgramData%\{random file name}.exe - added copy for Windows Vista and above
  • %ProgramData%\svchost.exe - added copy for Windows Vista and above running on virtual machine

(Note: %All Users Profile% is the All Users or Common profile folder, which is C:\Documents and Settings\All Users in Windows 2000, XP, and Server 2003, and C:\ProgramData in Windows Vista and 7.. %ProgramData% is a version of the Program Files folder where any user on a multi-user computer can make changes to programs. This is usually C:\ProgramData in Windows Vista and 7, or C:\Program Files on Windows 2000, XP (32-bit), and Server 2003, or C:\Program Files (x86) on Windows XP (64-bit).)

It injects codes into the following process(es):

  • %System%\svchost.exe
  • %System%\msiexec.exe

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)

Autostart Technique

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

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer\Run
{random number} = "%ProgramData%\{random file name}.exe" (For Windows Vista and above)

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer\Run
{random number} = "%All Users Profile%\{random file name}.exe"

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Run
SunJavaUpdateSched = "%ProgramData%\svchost.exe" (For Windows Vista and above running on Virtual Machine)

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Run
SunJavaUpdateSched = "%All Users Profile%\svchost.exe" (For versions lower than Windows Vista running on Virtual Machine)

It modifies the following registry entries to ensure it automatic execution at every system startup:

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\run
SunJavaUpdateSched = "%All Users Profile%\svchost.exe"

(Note: The default value data of the said registry entry is "%Java Update Folder%\jusched.exe".)

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\run
SunJavaUpdateSched = "%ProgramData%\svchost.exe" (For Windows Vista and above running on Virtual Machine)

(Note: The default value data of the said registry entry is "%Java Update Folder%\jusched.exe".)

Other System Modifications

This backdoor adds the following registry keys:

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\policies\
Explorer
Run =

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

HKEY_LOCAL_MACHINE\System\CurrentControlSe\
Services\SharedAcces\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
%System%\msiexec.exe = "%System%\msiexec.exe:*:Generic Host Process"

HKEY_LOCAL_MACHINE\System\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
%System%\svchost.exe = "%System%\svchost.exe:*:Generic Host Process"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
{malware path and file name} = "{malware path and file name}:*:Enabled:Compd bibionid perfecti"

Backdoor Routine

This backdoor connects to the following URL(s) to send and receive commands from a remote malicious user:

  • http://{BLOCKED}a.ru/beijing.php
  • http://{BLOCKED}s.pl/qingdao.php
  • http://{BLOCKED}i.ru/warradale.php
  • http://{BLOCKED}x.pl/villahermosa.php
  • http://www.{BLOCKED}ov.net/goto.php?num=146897

As of this writing, the said sites are inaccessible.

Other Details

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

  • update.microsoft.com

It deletes the initially executed copy of itself

NOTES:

When running in a Virtual Machine, this malwares opens Port:8000, which could be used for remote command execution.

It checks internet connection and tries to connect to the following sites every 5 minutes:

  • {BLOCKED}a.ru
  • {BLOCKED}s.pl
  • {BLOCKED}i.ru
  • {BLOCKED}x.pl

  SOLUTION

Minimum Scan Engine:

9.300

FIRST VSAPI PATTERN FILE:

10.176.02

FIRST VSAPI PATTERN DATE:

25 Jul 2013

VSAPI OPR PATTERN File:

10.177.00

VSAPI OPR PATTERN Date:

26 Jul 2013

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_ANDROM.JN

Step 3

Restart in Safe Mode

[ Learn More ]

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.

 
  • In HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\policies\Explorer
    • Run

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_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
    • SunJavaUpdateSched = "%ProgramData%\svchost.exe" (For Windows Vista and above running on Virtual Machine)
  • In HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
    • SunJavaUpdateSched = "%All Users Profile%\svchost.exe" (For versions lower than Windows Vista running on Virtual Machine)
  • In HKEY_LOCAL_MACHINE\System\CurrentControlSe\Services\SharedAcces\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
    • %System%\msiexec.exe = "%System%\msiexec.exe:*:Generic Host Process"
  • In HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
    • %System%\svchost.exe = "%System%\svchost.exe:*:Generic Host Process"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
    • {malware path and  file name} = "{malware path and file name}:*:Enabled:Compd bibionid perfecti"

Step 6

Restore this modified registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator’s help. You may also check out this Microsoft article first before modifying your computer's registry.

  • In HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\run
    • From: SunJavaUpdateSched = "%All Users Profile%\svchost.exe"
      To: SunJavaUpdateSched = "%Java Update Folder%\jusched.exe"
  • In HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\run
    • From: SunJavaUpdateSched = "%ProgramData%\svchost.exe"  (For Windows Vista and above running on Virtual Machine)
      To: SunJavaUpdateSched = "%Java Update Folder%\jusched.exe"

Step 7

Search and delete these files

[ 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.
  • %All Users Profile%\{random file name}.exe
  • %All Users Profile%\svchost.exe - For Operating Systems running on Virtual Machine.
  • %ProgramData%\{random file name}.exe - Added copy for Windows Vista and above.
  • %ProgramData%\svchost.exe - Added copy for Windows Vista and above running on Virtual Machine.

Step 8

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