BKDR_ZEGOST.GAN
Windows 2000, Windows XP, Windows Server 2003
Threat Type: Backdoor
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
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 itself after execution.
TECHNICAL DETAILS
161,892 bytes
EXE
Yes
21 Aug 2013
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:
- %Program Files%\Rukkka daiiq\Jlmidswu.exe
(Note: %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).)
It creates the following folders:
- %Program Files%\Rukkka daiiq
(Note: %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).)
Autostart Technique
This backdoor registers as a system service to ensure its automatic execution at every system startup by adding the following registry keys:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Ruguoe wuqanywax
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Migmyu kahrka
Other System Modifications
This backdoor adds the following registry entries:
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Ruguoe wuqanywax
ReleiceName = "Migmyu kahrka"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Migmyu kahrka
ConnectGroup = "Come On!!!"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Migmyu kahrka
MarkTime = "2013-06-02 20:20"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Migmyu kahrka
Description = "Auyzwg zpuusagi mondwkeavse"
Dropping Routine
This backdoor drops the following files:
- %System Root%\8756.vbs
(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)
Other Details
This backdoor deletes itself after execution.
This report is generated via an automated analysis system.
SOLUTION
9.300
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
Restart in Safe Mode
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\CurrentControlSet\Services
- Ruguoe wuqanywax
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
- Migmyu kahrka
Step 4
Delete this registry value
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\Ruguoe wuqanywax
- ReleiceName = "Migmyu kahrka"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\Migmyu kahrka
- ConnectGroup = "Come On!!!"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\Migmyu kahrka
- MarkTime = "2013-06-02 20:20"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\Migmyu kahrka
- Description = "Auyzwg zpuusagi mondwkeavse"
Step 5
Search and delete this file
- %System Root%\8756.vbs
Step 6
Search and delete this folder
- %Program Files%\Rukkka daiiq
Step 7
Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_ZEGOST.GAN. 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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