TROJ_LASSY.B
RDN/Generic Dropper!wc (McAfee); Trojan-Dropper.Win32.Agent.olqy (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt); Trojan horse Agent5.LVR (AVG)
Windows
![](/vinfo/imgFiles/legend.jpg)
Threat Type: Trojan
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
This Trojan 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
Arrival Details
This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
Autostart Technique
This Trojan 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\sslassy\Parameters
Other System Modifications
This Trojan adds the following registry keys:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
DataAccess\sslassy
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\MediaResources\msvideo
It adds the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\SvcHost
sslassy = "sslassy,_CHAR(0x05)_,_CHAR(0x02)_,N_CHAR(0x01)_,Microsoft Software Drivers"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\sslassy
Description = "Microsoft Software Drivers."
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\sslassy
DisplayName = "Microsoft Software Drivers"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\sslassy
ErrorControl = "1"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\sslassy
Group = "Com Infrastructure"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\sslassy
ObjectName = "LocalSystem"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\sslassy
Start = "2"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\sslassy
FailureAction = "{random values}"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\sslassy
ImagePath = "%SystemRoot%\system32\svchost -k sslassy"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\sslassy\Parameters
ServiceDll = "%System%\sslassy64.dl_"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\sslassy\Parameters
ServiceMain = "vMainde"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
DataAccess\sslassy
Install = "{malware path and file name}"
Other Details
This Trojan connects to the following possibly malicious URL:
- {BLOCKED}.192.234
It deletes itself after execution.
This report is generated via an automated analysis system.
SOLUTION
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\sslassy
- Parameters
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\DataAccess
- sslassy
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\MediaResources
- msvideo
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\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SvcHost
- sslassy = "sslassy,_CHAR(0x05)_,_CHAR(0x02)_,N_CHAR(0x01)_,Microsoft Software Drivers"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\sslassy
- Description = "Microsoft Software Drivers."
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\sslassy
- DisplayName = "Microsoft Software Drivers"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\sslassy
- ErrorControl = "1"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\sslassy
- Group = "Com Infrastructure"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\sslassy
- ObjectName = "LocalSystem"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\sslassy
- Start = "2"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\sslassy
- FailureAction = "{random values}"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\sslassy
- ImagePath = "%SystemRoot%\system32\svchost -k sslassy"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\sslassy\Parameters
- ServiceDll = "%System%\sslassy64.dl_"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\sslassy\Parameters
- ServiceMain = "vMainde"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\DataAccess\sslassy
- Install = "{malware path and file name}"
Step 5
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_LASSY.B. 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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