BKDR_SYMMI.NAD
VirTool:Win32/CeeInject.gen!KK (Microsoft), Backdoor.Win32.Symmi.qhz (Kaspersky), Downloader-FYH!7B697E2C0B8C (McAfee)
Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)
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
106,344 bytes
, EXE
Yes
24 Apr 2014
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 and executes the following files:
- %AppDataLocal%\vinitru.dll
(Note: %AppDataLocal% is the Local Application Data folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local on Windows Vista and 7.)
Autostart Technique
This backdoor creates the following registry entries to enable automatic execution of dropped component at every system startup:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
vinitru = "rundll32 "%AppDataLocal%\vinitru.dll",vinitru"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsfot\
Windows NT\CurrentVersion\Winlogon\
Notify\vinitru
DllName = "%AppDataLocal%\vinitru.dll"
Other System Modifications
This backdoor adds the following registry keys:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsfot\
Windows NT\CurrentVersion\Winlogon\
Notify\vinitru
It adds the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsfot\
Windows NT\CurrentVersion\Winlogon\
Notify\vinitru
Impersonate = "1"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsfot\
Windows NT\CurrentVersion\Winlogon\
Notify\vinitru
Asynchronous = "1"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsfot\
Windows NT\CurrentVersion\Winlogon\
Notify\vinitru
MaxWait = "1"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsfot\
Windows NT\CurrentVersion\Winlogon\
Notify\vinitru
aamscheck = "{hex value}"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsfot\
Windows NT\CurrentVersion\Winlogon\
Notify\vinitru
Startup = "vinitru"
It creates the following registry entry(ies) to bypass Windows Firewall:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
{malware path and file name} = "{malware path and file name}:*:Enabled:GeoTrans"
Other Details
This backdoor connects to the following possibly malicious URL:
- {BLOCKED}1.{BLOCKED}lo75.net
- {BLOCKED}0.{BLOCKED}lo75.net
- {BLOCKED}a.{BLOCKED}o75.net
SOLUTION
9.700
10.746.01
24 Apr 2014
10.747.00
24 Apr 2014
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
Scan your computer with your Trend Micro product and note files detected as BKDR_SYMMI.NAD
Step 3
Terminate a process file/s detected as BKDR_SYMMI.NAD
*Note: If the detected file/s is/are not displayed in theWindows Task Manager, continue doing the next steps.
Step 4
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\SOFTWARE\Microsfot\Windows NT\CurrentVersion\Winlogon\Notify
- vinitru
- vinitru
Step 5
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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
- vinitru = "rundll32 "%AppDataLocal%\vinitru.dll",vinitru"
- vinitru = "rundll32 "%AppDataLocal%\vinitru.dll",vinitru"
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
- {malware path}\{malware name} = "{malware path and file name}:*:Enabled:GeoTrans"
- {malware path}\{malware name} = "{malware path and file name}:*:Enabled:GeoTrans"
Step 6
Search and delete this file
- %AppDataLocal%\vinitru.dll
Step 7
Scan your computer with your Trend Micro product to delete files detected as BKDR_SYMMI.NAD. 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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