BKDR_SIMBOT.BK
Windows 2000, Windows XP, Windows Server 2003
Threat Type: Backdoor
Destructiveness: No
Encrypted: Yes
In the wild: Yes
OVERVIEW
Dropped by other malware
This backdoor may be dropped by other malware.
It executes commands from a remote malicious user, effectively compromising the affected system.
TECHNICAL DETAILS
178,920 bytes
EXE, TMP
Yes
20 Sep 2012
Compromises system security, Modifies system registry
Arrival Details
This backdoor may be dropped by the following malware:
Installation
This backdoor drops the following copies of itself into the affected system and executes them:
- %System%\msiehtc.exe
(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)
Autostart Technique
This backdoor adds the following registry entries to enable its automatic execution at every system startup:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Explorer\Run
msginit = "%System%\msiehtc.exe"
Other System Modifications
This backdoor adds the following registry keys:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Explorer
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Explorer\Run
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
ESENT\Process\msiehtc
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
ESENT\Process\msiehtc\
DEBUG
It adds the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
ESENT\Process\msiehtc\
DEBUG
Trace Level = ""
Backdoor Routine
This backdoor executes the following commands from a remote malicious user:
- Download and execute files
- Execute files
- Read files
- Enumerate drives
- Get drive information
- Enumerate processes
- Terminate processes
- Get process information
- Perform remote shell
It connects to the following URL(s) to send and receive commands from a remote malicious user:
- http://ftp.{BLOCKED}ofthelpa.net
It posts the following information to its command and control (C&C) server:
- Computer name
- IP address
- Infection time
- Mac address
- Malware process ID
- User name
SOLUTION
9.200
9.410.04
20 Sep 2012
9.411.00
21 Sep 2012
Step 1
For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.
Step 3
Identify and terminate files detected as BKDR_SIMBOT.BK
- 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 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\Microsoft\Windows\CurrentVersion\policies
- Explorer
- Explorer
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\ESENT\Process
- msiehtc
- msiehtc
Step 5
Scan your computer with your Trend Micro product to delete files detected as BKDR_SIMBOT.BK. 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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