BKDR_ANDROM.AJ

October 26, 2015
 Analysis by: Rika Joi Gregorio
 ALIASES:

Worm:Win32/Gamarue.I(Microsoft), W32/Androm.BJAS!tr.bdr(Fortinet), Trojan-Spy.Zbot(Ikarus), Win32/TrojanDownloader.Wauchos.X trojan(Eset)

 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:

  • In the wild: Yes

  OVERVIEW

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 listens on ports.

It deletes itself after execution.

  TECHNICAL DETAILS

File Size:

200,704 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

09 Dec 2013

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:

  • %ProgramData%\explorer.exe (Windows Vista and 7 only)
  • %All Users Profile%\explorer.exe
  • %All Users Profile%\{random}.exe

(Note: %ProgramData% is the Program Data folder, where it usually is C:\Program Files in Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\ProgramData in 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.. %All Users Profile% is the All Users folder, where it usually is C:\Documents and Settings\All Users on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\ProgramData 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 backdoor adds the following registry entries to enable its automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
Start WingMan Profiler = "%ProgramData%\explorer.exe" (Windows Vista and 7 only and if Java update is disabled in startup)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
Start WingMan Profiler = "%All Users Profile%\explorer.exe" (versions other than Windows Vista and 7 and if Java update is disabled in startup)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Explorer\Run
540 = "%All Users Profile%\{random}.exe"

Other System Modifications

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

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

Backdoor Routine

This backdoor listens on the following ports:

  • 3232

Other Details

This backdoor connects to the following possibly malicious URL:

  • http://{BLOCKED}inthebarn.com.au/yappo.exe
  • http://{BLOCKED}s.com/speedtest.php
  • http://{BLOCKED}mp.net/false.php
  • http://{BLOCKED}p.com/grow.exe
  • http://{BLOCKED}r.net/guns.php
  • http://www.{BLOCKED}men.de/fault.exe

It deletes itself after execution.

  SOLUTION

Minimum Scan Engine:

9.700

FIRST VSAPI PATTERN FILE:

10.462.07

FIRST VSAPI PATTERN DATE:

10 Dec 2013

VSAPI OPR PATTERN File:

10.463.00

VSAPI OPR PATTERN Date:

10 Dec 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

Restart in Safe Mode

[ Learn More ]

Step 3

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\policies\Explorer\Run
    • 540 = %All Users Profile%\{random}.exe
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • Start WingMan Profiler = "%ProgramData%\explorer.exe" (Windows Vista and 7 only and if Java update is disabled in startup)
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • Start WingMan Profiler = "%All Users Profile%\explorer.exe" (versions other than Windows Vista and 7 and if Java update is disabled in startup)
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
    • {malware path and file name} = "{malware path and file name}:*:Enabled:{malware file name}"

Step 4

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