BKDR_INJECT.DCX

July 19, 2013
 Analysis by: Alvin Bacani
 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 bypasses the Windows firewall. This allows the malware to perform its intended routine without being detected by an installed firewall.

It executes commands from a remote malicious user, effectively compromising the affected system. However, as of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

Ports:

TCP Port 443

File Size:

402,464 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

18 Jul 2013

Payload:

Connects to URLs/IPs

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 modifies the following registry entries to disable the Windows Firewall settings:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
%User Temp%\checkup.exe = "%User Temp%\checkup.exe:*:Enabled:check update"

Backdoor Routine

This backdoor opens the following port(s) where it listens for remote commands:

  • 8082

It executes the following commands from a remote malicious user:

  • Download Files
  • Executes Files
  • Terminates Files
  • Start Service
  • Stop Service
  • Send data to remote user

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

  • vps2.{BLOCKED}hoo.tk
  • {BLOCKED}.{BLOCKED}.31.34 via port 8989

However, as of this writing, the said sites are inaccessible.

Information Theft

This backdoor accepts the following parameters:

  • local - opens port
  • remote1 - connect to url
  • remote2 - connect to url

  SOLUTION

Minimum Scan Engine:

9.300

FIRST VSAPI PATTERN FILE:

10.162.09

FIRST VSAPI PATTERN DATE:

18 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

Terminate a malware/grayware process

[ Learn More ]

*Note: If the detected process is not displayed in theWindows Task Manager, continue doing the next steps.

     
    • %User Temp%\checkup.exe
    • %User Temp%\mokivae.exe

Step 3

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.
  • %User Temp%\checkup.exe
  • %User Temp%\mokivae.exe

Step 4

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\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
    • %User Temp%\checkup.exe    %User Temp%\checkup.exe:*:Enabled:check update

Step 5

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