ALIASES:

Backdoor:Win32/Haxdoor.gen!B (Microsoft); Generic Dropper.io (McAfee); Infostealer (Symantec); Haxdoor.Fam (Sunbelt); Trojan.Spy.Goldun.NEL (FSecure); Win32/Heur (AVG)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

 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.

It deletes itself after execution.

  TECHNICAL DETAILS

File Size: 91,648 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 12 Feb 2013

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:

  • %User Temp%\i_setup

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.)

Other System Modifications

This Trojan deletes the following files:

  • \pmta.exe

It adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon\
Notify\snjava

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\SafeBoot\Minimal\
java2.sys

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\SafeBoot\Network\
java2.sys

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon\
Notify\snjava
DllName = "snjava.dll"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon\
Notify\snjava
Startup = "snjava"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon\
Notify\snjava
Impersonate = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon\
Notify\snjava
Asynchronous = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon\
Notify\snjava
MaxWait = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon\
Notify\snjava
ngrvv = "[DB5370609CD5D2B7E]"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Cache
Persistent = "0"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\NPF
Start = "1"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\vmrawdsk
Start = "1"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
%System%\rundll32.exe = "%System%\rundll32.exe:*:Enabled:rundll32"

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\VMMEMCTL
Start = "1"

(Note: The default value data of the said registry entry is 2.)

It deletes the following registry keys:

HKEY_LOCAL_MACHINE\Software\Microsoft\
Internet Explorer\Extensions\{FB5F1910-F110-11d2-BB9E-00C04F795683}

HKEY_LOCAL_MACHINE\Software\Microsoft\
Internet Explorer\Toolbar

Dropping Routine

This Trojan drops the following files:

  • z98.bin
  • snjava.dll
  • java2.sys
  • %System%\drivers\npf.sys
  • %Program Files%\VMware\VMware Tools\Drivers\memctl\vmmemctl.sys
  • %Program Files%\VMware\VMware Tools\vmrawdsk.sys

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

Other Details

This Trojan deletes itself after execution.

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine: 9.300

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

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 NT\CurrentVersion\Winlogon\Notify
    • snjava
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SafeBoot\Minimal
    • java2.sys
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SafeBoot\Network
    • java2.sys

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 NT\CurrentVersion\Winlogon\Notify\snjava
    • DllName = "snjava.dll"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\Notify\snjava
    • Startup = "snjava"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\Notify\snjava
    • Impersonate = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\Notify\snjava
    • Asynchronous = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\Notify\snjava
    • MaxWait = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\Notify\snjava
    • ngrvv = "[DB5370609CD5D2B7E]"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Cache
    • Persistent = "0"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\NPF
    • Start = "1"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\vmrawdsk
    • Start = "1"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
    • %System%\rundll32.exe = "%System%\rundll32.exe:*:Enabled:rundll32"

Step 4

Restore these modified registry values

[ 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\SYSTEM\ControlSet001\Services\VMMEMCTL
    • From: Start = "1"
      To: Start = ""2""

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.
  • z98.bin
  • snjava.dll
  • java2.sys
  • %System%\drivers\npf.sys
  • %Program Files%\VMware\VMware Tools\Drivers\memctl\vmmemctl.sys
  • %Program Files%\VMware\VMware Tools\vmrawdsk.sys

Step 6

Search and delete this folder

[ 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.
  • %User Temp%\i_setup

Step 7

Scan your computer with your Trend Micro product to delete files detected as TROJ_DROPPER.UY. 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.

  • \pmta.exe

Step 9

Restore these deleted registry keys/values from backup

*Note: Only Microsoft-related keys/values will be restored. If the malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.

  • In HKEY_LOCAL_MACHINE\Software\Microsoft\Internet Explorer\Extensions
    • {FB5F1910-F110-11d2-BB9E-00C04F795683}
  • In HKEY_LOCAL_MACHINE\Software\Microsoft\Internet Explorer
    • Toolbar


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