BKDR_GUOQA.A
Windows 2000, Windows XP, Windows Server 2003
Threat Type: Backdoor
Destructiveness: No
Encrypted: No
In the wild: Yes
OVERVIEW
Dropped by other malware, Downloaded from the Internet
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.
It runs certain commands that it receives remotely from a malicious user. Doing this puts the affected computer and information found on the computer at greater risk. It connects to a website to send and receive information.
It retrieves specific information from the affected system.
TECHNICAL DETAILS
TCP Port 443
Varies
DLL
Yes
22 Jun 2012
Steals information
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 the following component file(s):
- %Program Files%\Windows NT\htrn.dll - also detected as BKDR_GUOQA.A
(Note: %Program Files% is the default Program Files folder, usually C:\Program Files.)
Its DLL component is injected to the following process(es):
- svchost.exe
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\6to4\Parameters
ServiceDll = %Program Files%\Windows NT\htrn.dll
Backdoor Routine
This backdoor opens the following port(s) where it listens for remote commands:
- 443
It executes the following command(s) from a remote malicious user:
- List running processes
- Terminate process
- Download and execute file
- Open a remote command shell access
- Write to a file
- Uninstall itself
- Reboot the system
It connects to the following websites to send and receive information:
- snrp.{BLOCKED}s.com
Information Theft
This backdoor retrieves the following information from the affected system:
- Computer name
- Local IP address
- Service pack
SOLUTION
9.200
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 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
- 6to4
- 6to4
Step 4
Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_GUOQA.A. 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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