Analysis by: Joseph Obed
 Modified by: Sabrina Lei Sioting

ALIASES:

Backdoor.Darkmoon (Symantec), BackDoor-AMQ.dr (McAfee)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel: Dropped by other malware, Downloaded from the Internet

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 does not have any propagation routine.

It does not have any downloading capability.

It logs a user's keystrokes to steal information.

  TECHNICAL DETAILS

Ports: Port 80
File Size: Varies
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 25 Apr 2012
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.

Installation

This backdoor drops the following non-malicious files:

  • %System Root%\asf
  • {malware path and filename}

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

It creates the following folders:

  • %System Root%\dfed

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

It adds the following mutexes to ensure that only one of its copies runs at any one time:

  • $#^@G#%^S
  • %1Sjfhtd8
  • &EJFUAE
  • )!Vo123
  • A^#KF&DFE
  • KDKD&^*#F
  • K^DJA^#FE

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
adobe = "{malware path}\{malware name}.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Active Setup\Installed Components\{0082ABF9-9309-614B-C2DD-C00CC33A8073}
StubPath = "%System%:mssendfull.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Active Setup\Installed Components\{9E41174A-B99F-F49D-5CD0-0EF87DF3A162}
StubPath = "%System%:msjbvpncon.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Active Setup\Installed Components\{2580E7A2-880C-351F-B4DC-8320A4AB551C}
StubPath = "%System%:mskeypro.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Active Setup\Installed Components\{343F94C0-7BF8-95A0-9892-DE5C539F2AF8}
StubPath = "%System%:msfullcomen.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Active Setup\Installed Components\{180DA249-E241-D1EA-A5D6-E400EFEC204F}
StubPath = "%System%:mcarmy.exe"

Other System Modifications

This backdoor adds the following registry keys as part of its installation routine:

HKEY_CURRENT_USER\Software\Local AppWizard-Generated Applications

HKEY_CURRENT_USER\Software\Local AppWizard-Generated Applications

HKEY_CURRENT_USER\Software\Local AppWizard-Generated Applications\
\Recent File List

HKEY_CURRENT_USER\Software\Local AppWizard-Generated Applications\
\Settings

HKEY_CURRENT_USER\Software\ations

HKEY_CURRENT_USER\Software\ations

HKEY_CURRENT_USER\Software\ations\
\Recent File List

HKEY_CURRENT_USER\Software\ations\
\Settings

Propagation

This backdoor does not have any propagation routine.

Backdoor Routine

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

  • TCP port 443

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

  • cs.{BLOCKED}k.com
  • {BLOCKED}e.sytes.net
  • {BLOCKED}rn.com
  • {BLOCKED}s.com
  • {BLOCKED}uz.com
  • {BLOCKED}yearleft.com

Download Routine

This backdoor does not have any downloading capability.

Information Theft

This backdoor logs a user's keystrokes to steal information.

Other Details

Based on analysis of the codes, it has the following capabilities:

  • Capture screen, audio, and webcam
  • Log keystrokes
  • List active ports
  • Manage open windows
  • Manage passwords
  • Manage registry, processes, services, devices, and installed applications
  • Perform multiple simultaneous transfers
  • Perform remote shell
  • Relay server
  • Search files
  • Share servers
  • Update, restart, terminates itself

NOTES:

This backdoor creates an Alternate Data Stream (ADS) copy of itself:

  • %System%:mcarmy.exe
  • %System%:msfullcomen.exe
  • %System%:msjbvpncon.exe
  • %System%:mskeypro.exe
  • %System%:mssendfull.exe

This allows the malware to hide itself from detection. It also allows it to execute whenever the Windows system folder is accessed.

  SOLUTION

Minimum Scan Engine: 9.200
VSAPI OPR PATTERN File: 8.941.00
VSAPI OPR PATTERN Date: 25 Apr 2012

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

Using Trend Micro Rootkit Buster

RootkitBuster is a rootkit scanner that can check through hidden files, registry entries, processes, drivers, and hooked system services.

To use this tool, do the following:

  1. Download the tool from the following link and extract it to a temporary folder:
    https://www.trendmicro.com/download/rbuster.asp
  2. Run the RootkitBuster.exe file.
  3. On the upper left corner, select the types of hidden items that you wish to scan. We recommend selecting all types.
  4. Click the Scan button.
  5. The system is infected by this malware if the Scan result is similar to the image below:

    rootkitbuster

Step 3

Terminate a process file/s detected as BKDR_POISON.SME4

[ Learn More ]

*Note: If the detected file/s is/are not displayed in theWindows Task Manager, continue doing the next steps.

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_CURRENT_USER\Software
    • ations
  • In HKEY_CURRENT_USER\Software
    • Local AppWizard-Generated Applications

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
    • adobe = "{malware path}\{malware name}.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Active Setup\Installed Components\{0082ABF9-9309-614B-C2DD-C00CC33A8073}
    • StubPath = "%System%:mssendfull.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Active Setup\Installed Components\{9E41174A-B99F-F49D-5CD0-0EF87DF3A162}
    • StubPath = "%System%:msjbvpncon.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Active Setup\Installed Components\{2580E7A2-880C-351F-B4DC-8320A4AB551C}
    • StubPath = "%System%:mskeypro.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Active Setup\Installed Components\{343F94C0-7BF8-95A0-9892-DE5C539F2AF8}
    • StubPath = "%System%:msfullcomen.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Active Setup\Installed Components\{180DA249-E241-D1EA-A5D6-E400EFEC204F}
    • StubPath = "%System%:mcarmy.exe"

Step 6

Search and delete these folders

[ 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.
  • %System Root%\dfed

Step 7

Search and delete these files

[ 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.
  • %System Root%\asf
  • {malware path and filename}

Step 8

Scan your computer with your Trend Micro product to delete files detected as BKDR_POISON.SME4. 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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