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BKDR_INJECT.CIT

November 30, 2012
 ALIASES:

Backdoor:Win32/Zegost.AD (Microsoft); [000020dc.EXE]:Generic BackDoor.t (McAfee); Trojan-GameThief.Win32.Magania.hujd (Kaspersky)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • 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.

  TECHNICAL DETAILS

File Size:

102,400 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

30 Nov 2012

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.

Other System Modifications

This backdoor deletes the following files:

  • %System%\6to4ex.dll

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

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\6to4
File = "{malware path and file name}"

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\6to4
Type = "4"

(Note: The default value data of the said registry entry is 20.)

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\6to4
Description = "{random characters}"

(Note: The default value data of the said registry entry is Provides DDNS name registration and automatic IPv6 connectivity over an IPv4 network. If this service is stopped, other computers may not be able to reach it by name and the machine will only have IPv6 connectivity if it is connected to a native IPv6 network. If this service is disabled, any other services that explicitly depend on this service will fail to start..)

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\6to4\Parameters
ServiceDll = "%System%\6to4ex.dll"

(Note: The default value data of the said registry entry is {random values}.)

Dropping Routine

This backdoor drops the following files:

  • %User Temp%\39468_rs.tmp

(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.)

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.300

Step 1

For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.

Step 2

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\SYSTEM\ControlSet001\Services\6to4
    • File = "{malware path and file name}"

Step 3

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\6to4
    • From: Type = "4"
      To: Type = ""20""
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\6to4
    • From: Description = "{random characters}"
      To: Description = ""Provides DDNS name registration and automatic IPv6 connectivity over an IPv4 network. If this service is stopped, other computers may not be able to reach it by name and the machine will only have IPv6 connectivity if it is connected to a native IPv6 network. If this service is disabled, any other services that explicitly depend on this service will fail to start.""
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\6to4\Parameters
    • From: ServiceDll = "%System%\6to4ex.dll"
      To: ServiceDll = ""{random values}""

Step 4

Search and delete this file

[ Learn More ]
There may be some component 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 Temp%\39468_rs.tmp

Step 5

Scan your computer with your Trend Micro product to delete files detected as BKDR_INJECT.CIT. 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 6

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.

  • %System%\6to4ex.dll


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