BKDR_KULUOZ.SM09

September 17, 2014
 Analysis by: Rhena Inocencio
 ALIASES:

TrojanDownloader:Win32/Kuluoz.D (Microsoft), Net-Worm.Win32.Aspxor.bqfk (Kaspersky)

 PLATFORM:

Windows

 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 executes commands from a remote malicious user, effectively compromising the affected system.

It retrieves specific information from the affected system.

  TECHNICAL DETAILS

File Size:

Varies

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

07 Aug 2014

Payload:

Compromises system security, Collects system information

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 and executes them:

  • %AppDataLocal%\{random}.exe

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

It adds the following processes:

  • svchost.exe

It injects itself into the following processes as part of its memory residency routine:

  • created svchost.exe

Autostart Technique

This backdoor adds the following registry entries to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
{random} = "%AppDataLocal%\{random}.exe"

Other System Modifications

This backdoor adds the following registry keys:

HKEY_CURRENT_USER\SOFTWARE\{random}

It adds the following registry entries as part of its installation routine:

HKEY_CURRENT_USER\SOFTWARE\{random}
{random} = "{hex values}"

Backdoor Routine

This backdoor executes the following commands from a remote malicious user:

  • idl - sleep/idle
  • run - download and execute arbitrary file
  • rem - uninstall itself
  • rdl - update copy of injected code in svchost and add encrypted code to registry
  • upd - update copy of main malware
  • red - edit registry

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

  • http://{BLOCKED}.{BLOCKED}6.181.62:8080
  • http://{BLOCKED}.{BLOCKED}.19.249:8080

Information Theft

This backdoor retrieves the following information from the affected system:

  • Malware Version
  • Virtualization Information
  • Running Debugger/Forensic Tools
  • User name
  • Processor type
  • OS version
  • Antivirus product
  • Firewall product

NOTES:

It checks if there is a running window with the following names:

  • 99929D61-1338-48B1-9433-D42A1D94F0D2
  • 99929D61-1338-48B1-9433-D42A1D94F0D2-x32
  • 99929D61-1338-48B1-9433-D42A1D94F0D2-x64
  • APISpy32Class
  • Dumper
  • Dumper64
  • Iris - Version 5.59
  • PROCEXPL
  • PROCMON_WINDOW_CLASS
  • ProcessHacker
  • ProcessLasso_Notification_Class
  • SharedIntApp.exe
  • TSystemExplorerTrayForm.UnicodeClass
  • Tfrmrpcap
  • VBoxService.exe
  • VBoxTray.exe
  • VMwareDragDetWndClass
  • VMwareSwitchUserControlClass
  • WdcWindow
  • iptools.exe
  • prl_cc.exe
  • prl_tools.exe
  • vmsrvc.exe
  • vmtoolsd.exe
  • vmusrvc.exe
  • wireshark.exe

It checks for the following Service Disk or BIOS related registry information to check if it is running under virtualization:

  • AMIBI
  • PRLS
  • PTLTD
  • VMWare
  • Vbox
  • Virtual

  SOLUTION

Minimum Scan Engine:

9.700

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

Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

Step 3

Scan your computer with your Trend Micro product and note files detected as BKDR_KULUOZ.SM09

Step 4

Restart in Safe Mode

[ Learn More ]

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_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • {random} = "%AppDataLocal%\{random}.exe"

Step 6

Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_KULUOZ.SM09. 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 7

The following created files/folders/registry keys/registry entries cannot be identified by the user since there are no reference values in the created key. The only way it can be identified is by comparing the present system information with a backup. Note that the said components do not have to be deleted since it won't be harmful to the system.

 
  • In HKEY_CURRENT_USER\SOFTWARE
    • {random}


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