BKDR_SYMMI.ABC
Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)
![](/vinfo/imgFiles/legend.jpg)
Threat Type: Trojan
Destructiveness: No
Encrypted: Yes
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 executes commands from a remote malicious user, effectively compromising the affected system.
TECHNICAL DETAILS
151,552 bytes
EXE
Yes
11 Jun 2014
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.
Installation
This Trojan drops the following files:
- %AppDataLocal%\otrukos.dll -- detected as BKDR_SYMMI.ABC
(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.)
It adds the following mutexes to ensure that only one of its copies runs at any one time:
- "HBCN-O3CET-JKHAN"
Autostart Technique
This Trojan creates the following registry entries to enable automatic execution of dropped component at every system startup:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
otrukos = "rundll32 "%AppDataLocal%\otrukos.dll",otrukos"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon\
Notify\otrukos
DllName = "%AppDataLocal%\otrukos.dll"
Other System Modifications
This Trojan adds the following registry keys:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon\
Notify\otrukos
HKEY_CURRENT_USER\Software\Local AppWizard-Generated Applications
HKEY_CURRENT_USER\Software\Local AppWizard-Generated Applications\
{malware name}
HKEY_CURRENT_USER\Software\Local AppWizard-Generated Applications\
{malware name}\Recent File List
HKEY_CURRENT_USER\Software\Local AppWizard-Generated Applications\
{malware name}\Settings
It adds the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon\
Notify\otrukos
MaxWait = "dword:00000001"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon\
Notify\otrukos
Startup = "otrukos"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon\
Notify\otrukos
Asynchronous = "dword:00000001"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon\
Notify\otrukos
Impersonate = "dword:00000001"
Backdoor Routine
This Trojan executes the following commands from a remote malicious user:
- Download and execute arbitrary files
- Upload files
- Modifies system settings
It connects to the following URL(s) to send and receive commands from a remote malicious user:
- {BLOCKED}1.{BLOCKED}pizzaeater.me.uk
- {BLOCKED}a.{BLOCKED}pizzaeater.me.uk
- {BLOCKED}3.{BLOCKED}pizzaeater.me.uk
SOLUTION
9.700
Step 1
Identify and delete files detected as BKDR_SYMMI.ABC using either the Startup Disk or Recovery Console
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\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\Notify
- otrukos
- otrukos
- In HKEY_CURRENT_USER\Software
- Local AppWizard-Generated Applications
- Local AppWizard-Generated Applications
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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
- otrukos = "rundll32 "%AppDataLocal%\otrukos.dll",otrukos"
- otrukos = "rundll32 "%AppDataLocal%\otrukos.dll",otrukos"
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
- {malware path and file name} = "{malware path and file name}:*:Enabled:{malware file name}"
- {malware path and file name} = "{malware path and file name}:*:Enabled:{malware file name}"
Step 5
Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_SYMMI.ABC . 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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