BKDR_SCAR.TU
Trojan.Gen (Symantec); Trojan.Win32.Scar.enhg (Kaspersky)
Windows 2000, Windows XP, Windows Server 2003
Threat Type: Backdoor
Destructiveness: No
Encrypted: No
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.
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 deletes the initially executed copy of itself.
TECHNICAL DETAILS
110,592 bytes
EXE
Yes
13 Sep 2011
Connects to URLs/IPs
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 copies of itself into the affected system:
- %Program Files%\NetServices\Schied.exe
(Note: %Program Files% is the default Program Files folder, usually C:\Program Files.)
It creates the following folders:
- %Program Files%\NetServices
(Note: %Program Files% is the default Program Files folder, usually C:\Program Files.)
Autostart Technique
This backdoor adds the following registry entries to enable its automatic execution at every system startup:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Active Setup\Installed Components\{A0XC6A98-A14C-J35H-46UD-F5AR862J2AH5}
StubPath = "%Program Files%\NetServices\Schied.exe"
Other System Modifications
This backdoor adds the following registry keys as part of its installation routine:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Active Setup\Installed Components\{A0XC6A98-A14C-J35H-46UD-F5AR862J2AH5}
Backdoor Routine
This backdoor executes the following command(s) from a remote malicious user:
- Execute command shell (cmd.exe)
- Execute process
- Log keystrokes
- Retrieve system information
It connects to the following websites to send and receive information:
- http://{BLOCKED}nny2017.rr.nu/mail.asp
- http://{BLOCKED}.sitelutions.com
Other Details
This backdoor deletes the initially executed copy of itself
NOTES:
This malware also connects to the aforementioned URLs to report system infection and to send system information such as the following:
- Host name
- OS version
- User name
- Volume information
SOLUTION
9.200
8.425.00
13 Sep 2011
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. Before you could do this, you must restart in Safe Mode. For instructions on how to do this, you may refer to this page If the preceding step requires you to restart in safe mode, you may proceed to edit the system registry.
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Active Setup\Installed Components
- {A0XC6A98-A14C-J35H-46UD-F5AR862J2AH5}
- {A0XC6A98-A14C-J35H-46UD-F5AR862J2AH5}
Step 4
Search and delete this folder
- %Program Files%\NetServices
Step 5
Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_SCAR.TU. 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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