BKDR_ZEGOST.YNTT
Windows
Threat Type: Backdoor
Destructiveness: No
Encrypted: Yes
In the wild: Yes
OVERVIEW
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 deletes the initially executed copy of itself.
TECHNICAL DETAILS
87,040 bytes
DLL
Yes
07 Aug 2016
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 a copy of itself in the following folders using different file names:
- %SystemRoot%\System32\DiskMgers.dll
It drops and executes the following files:
- {malware directory}\delete_dll.bat
- {malware directory}\_dll_Delete_Me__.bat (Used for deleting the initially executed copy)
Autostart Technique
This backdoor registers itself as a system service to ensure its automatic execution at every system startup by adding the following registry entries:
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\6to4\Parameters
ServiceDll = "%SystemRoot%\System32\DiskMgers.dll"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\6to4\Parameters
Description = "Supports System Event Notification Service (SENS), which provides automatic distribution of events to subscribing Component"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\6to4\Parameters
DisplayName = "COM+ Event System Files"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\6to4\Parameters
ImagePath = "%SystemRoot%\System32\svchost.exe -k netsvcs"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\6to4\Parameters
ObjectName = "LocalSystem"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\6to4\Parameters
Start = "2"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\6to4\Parameters
ErrorControl = "0"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\6to4\Parameters
Type = "272"
Backdoor Routine
This backdoor connects to the following URL(s) to send and receive commands from a remote malicious user:
- playball.{BLOCKED}s.info
- nvedia.{BLOCKED}s.info
It posts the following information to its command and control (C&C) server:
- OS version information
- Processor information
- Current usage of physical and virtual memory
Other Details
This backdoor does the following:
- This backdoor has the following capabilities:
- Download File
- Update Backdoor
- Shell Execute
- Shutdown System
- Uninstall Service
- Search Files
- Remove Directory
- Delete Files
- Delete Clipboard
It deletes the initially executed copy of itself
SOLUTION
9.800
12.700.03
07 Aug 2016
12.701.00
08 Aug 2016
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
Delete this registry key
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
- 6to4
Step 4
Search and delete this file
- {malware directory}\delete_dll.bat
- {malware directory}\_dll_Delete_Me__.bat
Step 5
Scan your computer with your Trend Micro product to delete files detected as BKDR_ZEGOST.YNTT. 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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