BKDR_ZEGOST.SM35
Windows


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.
TECHNICAL DETAILS
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 adds the following processes:
- cmd.exe /c ping 127.0.0.1 -n 1 && del /f/q "{malware file path and name}"
- %Windows%\SysWOW64\svchost.exe -k "serivces"
- %System%\serivces.exe "%System%\33622635.dll",MainThread
- %System%\PING.EXE ping 127.0.0.1 -n 1
(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.. %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)
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\CurrentControlSet\
Services\serivces
ImagePath = "%SystemRoot%\System32\svchost.exe -k serivces"
Other System Modifications
This Backdoor deletes the following files:
- {malware file path and name}
It adds the following registry keys:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\serivces\Parameters
It adds the following registry entries:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\serivces
Description = "{random characters}"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\serivces\Parameters
ServiceDll = "%System%\33622635.dll"
HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\
Microsoft\Windows NT\CurrentVersion\
Svchost
serivces = "s"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\serivces
Group = "X86"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\serivces
InstallTime = "2019-07-30 14:03"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\serivces
Type = "16"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\serivces
DisplayName = "System Remote Data Simulation Layer"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\serivces
Start = "SERVICE_AUTO_START"
Dropping Routine
This Backdoor drops the following files:
- %System%\serivces.exe
- %System%\33622635.dll
(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)
Other Details
This Backdoor connects to the following possibly malicious URL:
- http://sky.{BLOCKED}f.info
This report is generated via an automated analysis system.
SOLUTION
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
Identify and terminate files detected as BKDR_ZEGOST.SM35
- Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
- If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
- If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.
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\serivces
- Parameters
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\CurrentControlSet\services\serivces
- Description = "{random characters}"
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\serivces\Parameters
- ServiceDll = "%System%\33622635.dll"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Windows NT\CurrentVersion\Svchost
- serivces = "s"
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\serivces
- Group = "X86"
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\serivces
- InstallTime = "2019-07-30 14:03"
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\serivces
- Type = "16"
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\serivces
- DisplayName = "System Remote Data Simulation Layer"
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\serivces
- Start = "SERVICE_AUTO_START"
Step 5
Search and delete these components
- %System%\serivces.exe
- %System%\33622635.dll
Step 6
Scan your computer with your Trend Micro product to delete files detected as BKDR_ZEGOST.SM35. 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 the following Trend Micro Support pages for more information:
Step 7
Restore this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.
- {malware file path and name}
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