BKDR_KLOVBOT.E
TrojanDownloader:Win32/VB.TJ (Microsoft), Win32/Injector.KQO (ESET)
Windows
Threat Type: Backdoor
Destructiveness: No
Encrypted: Yes
In the wild: Yes
OVERVIEW
Downloaded from the Internet
This backdoor may be unknowingly downloaded by a user while visiting malicious websites.
It executes commands from a remote malicious user, effectively compromising the affected system. It connects to a website to send and receive information.
TECHNICAL DETAILS
98,304 bytes
EXE
Yes
09 Nov 2011
Connects to URLs/IPs, Compromises system security
Arrival Details
This backdoor may be unknowingly downloaded by a user while visiting malicious websites.
Installation
This backdoor drops the following copies of itself into the affected system:
- %Windows%\csrcs.exe
(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.)
It adds the following mutexes to ensure that only one of its copies runs at any one time:
- byvOlk
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\Run
Microsofts = %Windows%\csrcs.exe
Backdoor Routine
This backdoor executes the following commands from a remote malicious user:
- Adds or modifies the affected system's HOSTS files
- Visit Website (Hidden) - visits url without user's knowledge
- Download and Execute file
- Extract stored credentials from affected system (e.g. Filezilla)
- Navigate Website (visible) - visit url using the affected system's default web browser
It connects to the following websites to send and receive information:
- http://{BLOCKED}ss.net/winupdate
It posts the following information to its command and control (C&C) server:
- Logged-on Username
- IP Address
- Country
- OS version
- Date and Time
SOLUTION
9.700
8.562.02
8.563.00
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 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\CurrentVersion\Run
- Microsofts = %Windows%\csrcs.exe
- Microsofts = %Windows%\csrcs.exe
Step 4
Search and delete this file
- %Windows%\csrcs.exe
Step 5
Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_KLOVBOT.E. 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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