WORM_AUTORUN.FIL
Windows 2000, XP, Server 2003
Threat Type: Worm
Destructiveness: No
Encrypted: Yes
In the wild: Yes
OVERVIEW
Propagates via peer-to-peer networks, Propagates via removable drives
This worm arrives via removable drives. It may be dropped by other malware. It may be unknowingly downloaded by a user while visiting malicious websites.
It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.
It opens a random port to allow a remote user to connect to the affected system. Once a successful connection is established, the remote user executes commands on the affected system. It connects to a website to send and receive information.
TECHNICAL DETAILS
580,454 bytes
PE
Yes
10 Nov 2010
Compromises system security, Connects to URLs/Ips
Arrival Details
This worm arrives via removable drives.
It may be dropped by other malware.
It may be unknowingly downloaded by a user while visiting malicious websites.
Installation
This worm drops the following files:
- %System%\autorun.ini - copy of autorun.inf
- %System%\autorun.i - copy of autorun.inf
(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.)
It drops the following copies of itself into the affected system:
- %System%\csrcs.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 worm adds the following registry entries to enable its automatic execution at every system startup:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Explorer\Run
csrcs = %System%\csrcs.exe
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\RunServices
csrcs = %System%\csrcs.exe
It modifies the following registry entries to ensure it automatic execution at every system startup:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
Shell = Explorer.exe csrcs.exe
(Note: The default value data of the said registry entry is Explorer.exe.)
Other System Modifications
This worm adds the following registry keys as part of its installation routine:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
DRM\amty
It modifies the following registry entries to hide files with Hidden attributes:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Hidden = 2
(Note: The default value data of the said registry entry is 1.)
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
ShowSuperHidden = 0
(Note: The default value data of the said registry entry is 1.)
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
SuperHidden = 0
(Note: The default value data of the said registry entry is 1.)
Propagation
This worm drops the following copy(ies) of itself in all removable drives:
- uqskrw.exe
It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.
It modifies the contents of an existing AUTORUN.INF file to automatically execute its dropped copy. It does this by adding the following strings in the .INF file:
- ;{garbage}
- [AutorUN]
- ;{garbage}
- acTioN=view files
- ;{garbage}
- UseAutoPLay=1
- ;{garbage}
- OepN=UQSKrw.ExE
- ;{garbage}
- aCTIon=@uqskrw.exe
- ;{garbage}
- sheLL\OpEn\ComMANd=uqSkRW.exe
- ;{garbage}
- sHell\OPEn\DEfAult=1
- ;{garbage}
- IcON=%systEM%\sheLl32.DLl,7
- ;{garbage}
Backdoor Routine
This worm opens a random port to allow a remote user to connect to the affected system. Once a successful connection is established, the remote user executes commands on the affected system.
It connects to the following websites to send and receive information:
- http://{BLOCKED}e.extasix.com
Other Details
Based on analysis of the codes, it has the following capabilities:
- It drops copies to shared folders used by the following P2P applications:
- FrostWir
- eMule
- Kazaa
- LimeWire
- Shareaza
- DC++
- Ares
- It gathers the following information:
- User Name
- Computer Name
- OS Version
- OS Service Pack
- Drive Serial
- OS Language
- System Directory
It connects to the following URL(s) to get the affected system's IP address:
- http://www.whatsmyip.com/automation/n09230945.asp
SOLUTION
8.900
under testing
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
Identify and terminate files detected as WORM_AUTORUN.FIL
- 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 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\policies\Explorer\Run
- csrcs = %System%\csrcs.exe
- csrcs = %System%\csrcs.exe
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\RunServices
- csrcs = %System%\csrcs.exe
- csrcs = %System%\csrcs.exe
Step 4
Restore this modified 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 NT\CurrentVersion\Winlogon
- From: Shell = Explorer.exe csrcs.exe
To: Shell = Explorer.exe
- From: Shell = Explorer.exe csrcs.exe
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
- From: Hidden = 2
To: Hidden = 1
- From: Hidden = 2
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
- From: ShowSuperHidden = 0
To: ShowSuperHidden = 1
- From: ShowSuperHidden = 0
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
- From: SuperHidden = 0
To: SuperHidden = 1
- From: SuperHidden = 0
Step 5
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\DRM
- amty
- amty
Step 6
Search and delete this file
%System%\autorun.i
Step 7
Search and delete AUTORUN.INF files created by WORM_AUTORUN.FIL that contain these strings
;{garbage}
[AutorUN]
;{garbage}
acTioN=view files
;{garbage}
UseAutoPLay=1
;{garbage}
OepN=UQSKrw.ExE
;{garbage}
aCTIon=@uqskrw.exe
;{garbage}
sheLL\OpEn\ComMANd=uqSkRW.exe
;{garbage}
sHell\OPEn\DEfAult=1
;{garbage}
IcON=%systEM%\sheLl32.DLl,7
;{garbage}
Step 8
Scan your computer with your Trend Micro product to delete files detected as WORM_AUTORUN.FIL. 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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