Analysis by: Roland Dela Paz

ALIASES:

Symantec : W32.Harakit; Mcafee : [.au3]:W32/Autorun.worm.zf.gen

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel: Propagates via removable drives

This worm adds registry entries to enable its automatic execution at every system startup. It modifies registry entries to enable its automatic execution at every system startup.

It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system. It uses icons similar to those of legitimate applications to entice a user to click them.

  TECHNICAL DETAILS

File Size: 675,106 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 11 Jan 2011
Payload: Connects to URLs/Ips

Installation

This worm drops the following copies of itself into the affected system:

  • %System%\csrcs.exe
  • %System%\{numbers}.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.inf - autorun component
  • [DRIVE]:\xerfoj1 - empty file

(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

It modifies the following registry entry(ies) to enable its 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:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
DRM\amty

Propagation

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

  • {random}.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:

;{garbage codes}
[AuTOrUn
;{garbage codes}
open={random}.exe
;{garbage codes}
shell\open\Command={random}.exe
;{garbage codes}
shell\open\Default=1
;{garbage codes}

It uses icons similar to those of legitimate applications to entice a user to click them.

Other Details

This worm connects to the following URL(s) to get the affected system's IP address:

  • http://www.whatismyip.com/

It connects to the following possibly malicious URL:

  • http://{BLOCKED}xh.dip.jp:38544/po.php - inaccessible as of this writing
  • http://{BLOCKED}xh.dip.jp:38544/limp.gif - contains garbage codes

It does the following:

  • It connects to http://{BLOCKED}atebay.org/ to check for top software downloads

  SOLUTION

Minimum Scan Engine: 8.900
VSAPI PATTERN File: 7.760.06
VSAPI PATTERN Date: 11 Jan 2011
VSAPI PATTERN Date: 1/11/2011 12:00:00 AM

Step 1

For Windows ME and XP 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_UTOTI.DD

[ Learn More ]
  1. For Windows 98 and ME users, Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
  2. 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.
  3. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

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\CurrentVersion\Winlogon
    • From: Shell = Explorer.exe csrcs.exe
      To: Shell = Explorer.exe

Step 4

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.

  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\DRM
    • amty

Step 5

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

Step 6

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.inf
[DRIVE]:\xerfoj1

Step 7

Search and delete AUTORUN.INF files created by WORM_UTOTI.DD that contain these strings

[ Learn More ]
;{garbage codes}
[AuTOrUn
;{garbage codes}
open={random}.exe
;{garbage codes}
shell\open\Command={random}.exe
;{garbage codes}
shell\open\Default=1
;{garbage codes}

Step 8

Scan your computer with your Trend Micro product to delete files detected as WORM_UTOTI.DD 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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