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TROJ_RENOS.AUJ

October 03, 2012
 ALIASES:

Rogue:Win32/FakePlus (Microsoft); FakeAlert-DF (McAfee); Downloader.MisleadApp (Symantec); Trojan-Downloader.Win32.FraudLoad.dyy (Kaspersky); Antivirus Plus (fs) (Sunbelt); Trojan.Generic.1558941 (FSecure)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

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

It modifies files, disabling programs and applications from properly running.

  TECHNICAL DETAILS

File Size:

419,328 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

03 Oct 2012

Arrival Details

This Trojan 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 Trojan creates the following folders:

  • %Program Files%\Antivirus Plus
  • %Start Menu%\Programs\Antivirus Plus

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

Other System Modifications

This Trojan modifies the following files:

  • %System%\rundll32.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 adds the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
%System%\rundll32.exe = "%System%\rundll32.exe:*:Enabled:rundll32"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
{malware path and file name} = "{malware path and file name}:*:enabled:installer"

Dropping Routine

This Trojan drops the following files:

  • %System%\avp.id
  • %System%\InternetExplorer.dll
  • %System%\dmns.cfg
  • %Program Files%\Antivirus Plus\AntivirusPlus.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.. %Program Files% is the default Program Files folder, usually C:\Program Files.)

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://{BLOCKED}adantivirusplus.com/cb/real.php?id=199a7
  • http://{BLOCKED}e.com
  • http://{BLOCKED}adantivirusplus.com/install/AntivirusPlus.exe
  • http://{BLOCKED}adantivirusplus.com/cb/installs.php?id=199a7
  • http://{BLOCKED}adantivirusplus.com/install/InternetExplorer.dll
  • http://{BLOCKED}adantivirusplus.com/cfg/dmns.cfg

This report is generated via an automated analysis system.

  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

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\SYSTEM\ControlSet001\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
    • %System%\rundll32.exe = "%System%\rundll32.exe:*:Enabled:rundll32"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
    • {malware path and file name} = "{malware path and file name}:*:enabled:installer"

Step 3

Search and delete these files

[ 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%\avp.id
  • %System%\InternetExplorer.dll
  • %System%\dmns.cfg
  • %Program Files%\Antivirus Plus\AntivirusPlus.exe

Step 4

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.
  • %Program Files%\Antivirus Plus
  • %Start Menu%\Programs\Antivirus Plus

Step 5

Scan your computer with your Trend Micro product to delete files detected as TROJ_RENOS.AUJ. 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.

Step 6

Restore deleted/modified files and/or registry entries from backup

*Note: Only Microsoft-related files/keys/values will be restored. If this malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.

    • %System%\rundll32.exe


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