This malware is related to a spam run that displays a malicious link which leads to the download of KULUOZ malware.
To get a one-glance comprehensive view of the behavior of this Backdoor, refer to the Threat Diagram shown below.

This Backdoor arrives as attachment to mass-mailed email messages.
It executes commands from a remote malicious user, effectively compromising the affected system. It connects to a website to send and receive information.
It retrieves specific information from the affected system.
Arrival Details
This Backdoor arrives as attachment to mass-mailed email messages.
Installation
This Backdoor drops the following copies of itself into the affected system:
- %Application Data%\{random}.exe
(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, and 8.)
It adds the following processes:
It adds the following mutexes to ensure that only one of its copies runs at any one time:
It injects itself into the following processes as part of its memory residency routine:
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} = "%Application Data%\{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 websites to send and receive information:
- http://{BLOCKED}.{BLOCKED}.66:443
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:
This malware checks if there is a running window with the following name:
- wireshark.exe
- Tfrmrpcap
- iptools.exe
- Iris - Version 5.59
- ProcessLasso_Notification_Class
- TSystemExplorerTrayForm.UnicodeClass
- PROCMON_WINDOW_CLASS
- PROCEXPL
- WdcWindow
- ProcessHacker
- 99929D61-1338-48B1-9433-D42A1D94F0D2-x64
- 99929D61-1338-48B1-9433-D42A1D94F0D2-x32
- 99929D61-1338-48B1-9433-D42A1D94F0D2
- Dumper
- Dumper64
- APISpy32Class
- VMwareDragDetWndClass
- VMwareSwitchUserControlClass
- vmtoolsd.exe
- prl_cc.exe
- prl_tools.exe
- SharedIntApp.exe
- VBoxTray.exe
- VBoxService.exe
- vmusrvc.exe
- vmsrvc.exe
It checks if Service Disk or Bios registries are under Virtualization:
- VMWare
- PTLTD
- Virtual
- PRLS
- Vbox
- AMIBI
It checks if the following registry keys exist:
- SYSTEM\CurrentControlSet\Enum\PCI\VEN_15AD&DEV_0774&SUBSYS_040515AD&REV_00
- SYSTEM\CurrentControlSet\Enum\PCI\VEN_15AD&DEV_0774&SUBSYS_074015AD&REV_00
- SYSTEM\CurrentControlSet\Enum\PCI\VEN_80EE&DEV_CAFE&SUBSYS_00000000&REV_00
- SYSTEM\CurrentControlSet\Enum\PCI\VEN_5333&DEV_8811&SUBSYS_00000000&REV_00
- SYSTEM\CurrentControlSet\Enum\PCI\VEN_80EE&DEV_BEEF&SUBSYS_00000000&REV_00
- HARDWARE\ACPI\DSDT\PTLTD__
- HARDWARE\ACPI\DSDT\VBOX__
- HARDWARE\ACPI\DSDT\AMIBI
Step 1
Before doing any scans, Windows 7, Windows 8, Windows 8.1, and Windows 10 users must disable System Restore to allow full scanning of their computers.
Step 2
Scan your computer with your Trend Micro product and note files detected as BKDR_KULUOZ.ED
Step 3
Restart in Safe Mode
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To restart in Safe Mode:
• For Windows 2000 users
- Restart your computer.
- Press F8 when you see the Starting Windows bar at the bottom of the screen.
- Choose the Safe Mode option from the Windows Advanced Options menu then press Enter.
• For Windows XP users
- Restart your computer.
- Press F8 after the Power-On Self Test (POST) routine is done. If the Windows Advanced Options menu does not appear, try restarting then pressing F8 several times when the POST screen appears.
- Choose the Safe Mode option from the Windows Advanced Options menu then press Enter.
• For Windows Server 2003 users
- Restart your computer.
- Press F8 after Windows starts up. If the Windows Advanced Options menu does not appear, try restarting again and pressing F8 several times afterward.
- On the Windows Advanced Option menu, use the arrow keys to select Safe Mode then press Enter.
• For Windows Vista, Windows 7, and Windows Server 2008 users
- Restart your computer.
- Press F8 after the Power-On Self Test (POST) routine is done. If the Advanced Boot Options menu does not appear, try restarting and then pressing F8 several times after the POST screen is displayed.
- On the Advanced Boot Options menu, use the arrow keys to select the Safe Mode option, and then press Enter.
• For Windows 8, Windows 8.1, and Windows Server 2012 users
- Access the Charms bar by moving your mouse pointer to the upper right corner of the screen.
- Move your mouse pointer down and click Settings>Change your PC Settings.
- In the left panel, click General.
- In the right panel, scroll down to the bottom to find the Advanced startup section, then click the Restart now button and wait for the system to restart.
- In the Advanced Startup menu, click Troubleshoot>Advanced Options>Startup Settings>Restart and wait for the system to restart.
- In the Startup Settings menu, press 4 to enable safe mode.
Step 4
Delete this registry value
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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} = "%Application Data%\{random}.exe"
To delete the registry value this malware/grayware created:
- Open Registry Editor.
» For Windows 2000, Windows XP, and Windows Server 2003 users, click Start>Run, type regedit in the text box provided, and then press Enter.
» For Windows Vista, Windows 7, and Windows Server 2008 users, click the Start button, type regedit in the Search input field then press Enter.
» For Windows 8, Windows 8.1, and Windows Server 2012 users, right-click on the lower-left corner of the screen, click Run, type regedit in the text box provided, and then press Enter.
RESTORE
Close Registry Editor.Step 5
Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_KULUOZ.ED. 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
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
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