WORM_OTORUN.BF


 ALIASES:

Worm:Win32/Tupym.A (Microsoft); W32/Tupym.worm (McAfee); W32.Svich (Symantec); Trojan.Win32.Patched.lx (Kaspersky); W32/AutoRun-BUC (Sophos); Trojan.Win32.AutoIT.gen (v) (Sunbelt); Trojan horse Generic32.AORF (AVG)

 PLATFORM:

Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This worm arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

  TECHNICAL DETAILS

File Size:

879,617 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

10 Sep 2014

Arrival Details

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

  • %System%\system3_.exe
  • %Windows%\system3_.exe

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.. %Windows% is the Windows folder, which is usually C:\Windows.)

Autostart Technique

This worm adds the following registry entries to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
Yahoo Messengger = "%System%\system3_.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 system3_.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\Policies\
Microsoft\Internet Explorer\Control Panel

HKEY_CURRENT_USER\Software\Policies\
Microsoft\Internet Explorer\Control Panel

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
WorkgroupCrawler\Shares

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Schedule
AtTaskMaxHours = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
WorkgroupCrawler\Shares
shared = "\New Folder.exe"

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer\Main
Default_Page_URL = "http://www.{BLOCKED}mworld.50webs.com"

(Note: The default value data of the said registry entry is http://www.microsoft.com/isapi/redir.dll?prd=ie&pver=6&ar=msnhome.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer\Main
Default_Search_URL = "http://www.{BLOCKED}mworld.50webs.com"

(Note: The default value data of the said registry entry is http://www.microsoft.com/isapi/redir.dll?prd=ie&ar=iesearch.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer\Main
Search Page = "http://www.{BLOCKED}mworld.50webs.com"

(Note: The default value data of the said registry entry is http://www.microsoft.com/isapi/redir.dll?prd=ie&ar=iesearch.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer\Main
Start Page = "http://www.{BLOCKED}mworld.50webs.com"

(Note: The default value data of the said registry entry is http://www.microsoft.com/isapi/redir.dll?prd={SUB_PRD}&clcid={SUB_CLSID}&pver={SUB_PVER}&ar=home.)

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
Start Page = "http://www.{BLOCKED}mworld.50webs.com"

(Note: The default value data of the said registry entry is http://www.microsoft.com/isapi/redir.dll?prd=ie&pver=6&ar=msnhome.)

Dropping Routine

This worm drops the following files:

  • d:\New Folder.exe
  • d:\system3_.exe
  • d:\autorun.inf

Other Details

This worm connects to the following possibly malicious URL:

  • http://h1.{BLOCKED}y.com/asdb000/setting.ini
  • http://h1.{BLOCKED}y.com/set/setting.ini
  • http://h1.{BLOCKED}y.com/asdb002/setting.ini
  • http://h1.{BLOCKED}y.com/asdb004/setting.ini
  • http://h1.{BLOCKED}y.com/asdb006/setting.ini
  • http://h1.{BLOCKED}y.com/asdb008/setting.ini
  • http://h1.{BLOCKED}y.com/asdb010/setting.ini
  • http://h1.{BLOCKED}y.com/asdb012/setting.ini
  • http://h1.{BLOCKED}y.com/asdb014/setting.ini
  • http://h1.{BLOCKED}y.com/asdb016/setting.ini
  • http://h1.{BLOCKED}y.com/asdb018/setting.ini
  • http://h1.{BLOCKED}y.com/asdb020/setting.ini
  • http://h1.{BLOCKED}y.com/asdb022/setting.ini
  • http://h1.{BLOCKED}y.com/asdb024/setting.ini
  • http://h1.{BLOCKED}y.com/asdb026/setting.ini
  • http://h1.{BLOCKED}y.com/asdb028/setting.ini
  • http://h1.{BLOCKED}y.com/asdb030/setting.ini
  • http://h1.{BLOCKED}y.com/asdb032/setting.ini
  • http://h1.{BLOCKED}y.com/asdb034/setting.ini
  • http://h1.{BLOCKED}y.com/asdb036/setting.ini
  • http://h1.{BLOCKED}y.com/asdb038/setting.ini
  • http://h1.{BLOCKED}y.com/asdb040/setting.ini
  • http://h1.{BLOCKED}y.com/asdb042/setting.ini
  • http://h1.{BLOCKED}y.com/asdb044/setting.ini
  • http://h1.{BLOCKED}y.com/asdb046/setting.ini
  • http://h1.{BLOCKED}y.com/asdb048/setting.ini
  • http://h1.{BLOCKED}y.com/asdb050/setting.ini
  • {BLOCKED}224.183
  • {BLOCKED}.161.109

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.700

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

Identify and delete files detected as WORM_OTORUN.BF using either the Startup Disk or Recovery Console

[ Learn More ]

Step 3

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\Policies\Microsoft\Internet Explorer
    • Control Panel
  • In HKEY_CURRENT_USER\Software\Policies\Microsoft\Internet Explorer
    • Control Panel
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\WorkgroupCrawler
    • Shares

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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • Yahoo Messengger = "%System%\system3_.exe"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\Schedule
    • AtTaskMaxHours = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\WorkgroupCrawler\Shares
    • shared = "\New Folder.exe"

Step 5

Restore these modified registry values

[ Learn More ]

Important:Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator's help. You may also check out this Microsoft article first before modifying your computer's registry.

  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Main
    • From: Default_Page_URL = "http://www.{BLOCKED}mworld.50webs.com"
      To: Default_Page_URL = ""http://www.microsoft.com/isapi/redir.dll?prd=ie&pver=6&ar=msnhome""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Main
    • From: Default_Search_URL = "http://www.{BLOCKED}mworld.50webs.com"
      To: Default_Search_URL = ""http://www.microsoft.com/isapi/redir.dll?prd=ie&ar=iesearch""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Main
    • From: Search Page = "http://www.{BLOCKED}mworld.50webs.com"
      To: Search Page = ""http://www.microsoft.com/isapi/redir.dll?prd=ie&ar=iesearch""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Main
    • From: Start Page = "http://www.{BLOCKED}mworld.50webs.com"
      To: Start Page = ""http://www.microsoft.com/isapi/redir.dll?prd={SUB_PRD}&clcid={SUB_CLSID}&pver={SUB_PVER}&ar=home""
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
    • From: Start Page = "http://www.{BLOCKED}mworld.50webs.com"
      To: Start Page = ""http://www.microsoft.com/isapi/redir.dll?prd=ie&pver=6&ar=msnhome""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
    • From: Shell = "Explorer.exe system3_.exe"
      To: Shell = ""Explorer.exe""

Step 6

Search and delete these components

[ Learn More ]
There may be some components 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.
  • d:\New Folder.exe
  • d:\system3_.exe
  • d:\autorun.inf

Step 7

Scan your computer with your Trend Micro product to delete files detected as WORM_OTORUN.BF. 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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