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WORM_OTOTI.UK

October 09, 2012
 Modified by: Nice Yutuc
 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This worm arrives by connecting affected removable drives to a system.

It drops copies of itself into all the removable drives connected to an affected system. It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

  TECHNICAL DETAILS

File Size:

809,044 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

23 Mar 2012

Arrival Details

This worm arrives by connecting affected removable drives to a system.

Installation

This worm 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.)

It drops the following files:

  • %System%\autorun.i
  • %System%\autorun.in

(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\Current Version\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:

HKEY_LOCAL_MACHINE\Software\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
SuperHidden = 0

(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.)

Propagation

This worm drops copies of itself into all the removable drives connected to an affected system.

It drops the following copy(ies) of itself in all removable drives:

  • IeArGy.EXE

It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

The said .INF file contains the following strings:

;770QRNI6X6V4406SOPI1Q53RC1N9SMM89E04EDS702H1BF9015YI
;35ZA8X0X7VZ2657DP794PLU9IFE93SR5J466IPJ85A520C
;OULE97QM6KZ3YGR9G39700YG51012X058FP58T84UC0D94WRN7H96ZCE85SEA9D121U30ZL3Z4339CE3
;0C44
[AuTORun]
;4RP68A1MHL8EZQ91W49S7C8K28U5TC0F73ZN8MCR06OG0WOUC
;5P93OAOP25373E03TTB4A42H17MO14DU3B0RZETL1J5U6E9
;1S9FKS2043H4SX38L3137401R2LP48V824MQ41XG62Z83LZ5EQA93M
;45F27A231FCABAE1D96900290B42BDAC8EFB0E9DB727D2C7BFC81571
USEAutoPlay=1
;46KHFS6XXO583W929G439LQ0E7CR26P71R6NI2FQ0H3IZKXTCP5NSX3E5P
;1PG7
;7788HEF50
;248KRB9ZT3288W1FR8UG020RC7T27NOUXM9048
ShelL\oPEN\DEfaULt=1
IcON=%SYSTEM%\SHELL32.DLl,7
opEN=IeARGy.eXE
sHELl\opEN\cOMMAnD=IeArGy.EXE
;66RV4MP4R09WK1JR4QVVFD2J4851W07
;B2L3
;51CQP1250KLP9Y99UI72W184I6D5
ACtion=View files
ACTIon= @ieargy.exe
;4AZ5S04AGSM547619V8MI
;A3Q10S3SZ59AO5J7717S85KLJ9DU3S8LP6UR17H1DM4LU76U6684ANYX3U5

  SOLUTION

Minimum Scan Engine:

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

[ Learn More ]

Step 3

Restore this modified registry value

[ Learn More ]

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\Current Version\Winlogon
    • From: Shell = Explorer.exe csrcs.exe
      To: Explorer.exe
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • From: Hidden = 2
      To: 1
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • From: SuperHidden = 0
      To: 1
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • From: ShowSuperHidden = 0
      To: 1

Step 4

Delete this registry value

[ Learn More ]

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
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\RunServices
    • csrcs = %System%\csrcs.exe

Step 5

Delete this registry key

[ Learn More ]

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\DRM
    • amty

Step 6

Search and delete AUTORUN.INF files created by WORM_OTOTI.UK that contain these strings

[ Learn More ]
;770QRNI6X6V4406SOPI1Q53RC1N9SMM89E04EDS702H1BF9015YI ;35ZA8X0X7VZ2657DP794PLU9IFE93SR5J466IPJ85A520C ;OULE97QM6KZ3YGR9G39700YG51012X058FP58T84UC0D94WRN7H96ZCE85SEA9D121U30ZL3Z4339CE3 ;0C44 [AuTORun] ;4RP68A1MHL8EZQ91W49S7C8K28U5TC0F73ZN8MCR06OG0WOUC ;5P93OAOP25373E03TTB4A42H17MO14DU3B0RZETL1J5U6E9 ;1S9FKS2043H4SX38L3137401R2LP48V824MQ41XG62Z83LZ5EQA93M ;45F27A231FCABAE1D96900290B42BDAC8EFB0E9DB727D2C7BFC81571 USEAutoPlay=1 ;46KHFS6XXO583W929G439LQ0E7CR26P71R6NI2FQ0H3IZKXTCP5NSX3E5P ;1PG7 ;7788HEF50 ;248KRB9ZT3288W1FR8UG020RC7T27NOUXM9048 ShelL\oPEN\DEfaULt=1 IcON=%SYSTEM%\SHELL32.DLl,7 opEN=IeARGy.eXE sHELl\opEN\cOMMAnD=IeArGy.EXE ;66RV4MP4R09WK1JR4QVVFD2J4851W07 ;B2L3 ;51CQP1250KLP9Y99UI72W184I6D5 ACtion=View files ACTIon= @ieargy.exe ;4AZ5S04AGSM547619V8MI ;A3Q10S3SZ59AO5J7717S85KLJ9DU3S8LP6UR17H1DM4LU76U6684ANYX3U5

Step 7

Search and delete this file

[ Learn More ]
There may be some component files that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden files and folders in the search result. %System%\autorun.i
%System%\autorun.in

Step 8

Restart in normal mode and scan your computer with your Trend Micro product for files detected as WORM_OTOTI.UK. 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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