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TROJ_OFICLA.AR

October 08, 2012
 Analysis by: JessaD
 ALIASES:

Trojan:Win32/Oficla.AI (Microsoft), Generic.dx!vuy (McAfee) ,

 PLATFORM:

Windows 2000, XP, Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

This Trojan arrives as an attachment to email messages spammed by other malware/grayware or malicious users.

It resolves a Domain Naming System (DNS) host name or Internet Protocol (IP) address.

  TECHNICAL DETAILS

File Size:

Varies

File Type:

PE

File Compression:

UPX

Memory Resident:

Yes

Initial Samples Received Date:

12 Oct 2010

Arrival Details

This Trojan arrives as an attachment to email messages spammed by other malware/grayware or malicious users.

Installation

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

  • %User Profile%\Application Data\{random name}\csrss.exe

(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.)

It creates the following folders:

  • %User Profile%\Application Data\{random name}

(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.)

Autostart Technique

This Trojan 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 %User Profile%\Application Data\{random name}\csrss.exe

(Note: The default value data of the said registry entry is Explorer.exe.)

Other System Modifications

This Trojan adds the following line(s)/entry(ies) in the WIN.INI file:

  • [random characters_1]
  • {random characters_2 = random characters_3}

It adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft
setiasworld = {data}

It creates the following registry entry(ies) to bypass Windows Firewall:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
{malware path and file name}.exe = {malware path and file name}.exe:*:Enabled:ldrsoft

Other Details

This Trojan resolves a Domain Naming System (DNS) host name or Internet Protocol (IP) address.

  SOLUTION

Minimum Scan Engine:

8.900

FIRST VSAPI PATTERN FILE:

7.532.11

FIRST VSAPI PATTERN DATE:

12 Oct 2010

VSAPI OPR PATTERN File:

7.533.00

VSAPI OPR PATTERN Date:

13 Oct 2010

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

Scan your computer with your Trend Micro product and note files detected as TROJ_OFICLA.AR

Step 3

Restart in Safe Mode

[ Learn More ]

Step 4

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 %User Profile%\Application Data\{random name}\csrss.exe
      To: Shell = Explorer.exe

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_CURRENT_USER\Software\Microsoft
    • setiasworld = {data}
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
    • {malware path and file name}.exe = {malware path and file name}.exe:*:Enabled:ldrsoft

Step 6

Search and delete these folders

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result. %User Profile%\Application Data\{random name}

Step 7

Remove the following string/s that this malware/grayware added to these system configuration files

[ Learn More ]

[random characters_1]
{random characters_2 = random characters_3}

Step 8

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