TROJ_DELF.IHI

May 08, 2013
 ALIASES:

Trojan:Win32/Adialer.GA (Microsoft); Generic StartPage.f (McAfee); Dialer.ExDialer (Symantec); Trojan.Win32.Dialer.ga (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt); Win32/PEStealth (AVG)

 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 deletes itself after execution.

  TECHNICAL DETAILS

File Size:

41,536 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

08 May 2013

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 drops the following copies of itself into the affected system:

  • %System%\ShellExt\CNTR.EXE

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

Other System Modifications

This Trojan deletes the following files:

  • %System Root%\$$del.bat
  • %System%\ShellExt\CNTR.EXE
  • %System%\$$del.bat

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.. %System% is the Windows system folder, which is usually C:\Windows\System32.)

It adds the following registry keys:

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Uninstall\
{86C43BC7-2319-4322-88FF-9FC402B08B4D}

HKEY_CURRENT_USER\Software\Freeware\
{FFB51760-344E-4FFB-BFFF-4B18C7AC1D63}

HKEY_CURRENT_USER\Software\Freeware\
{FFB51760-344E-4FFB-BFFF-4B18C7AC1D63}\{86C43BC7-2319-4322-88FF-9FC402B08B4D}\Book\
3202

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
{86C43BC7-2319-4322-88FF-9FC402B08B4D}
DisplayName = "exdialer"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
{86C43BC7-2319-4322-88FF-9FC402B08B4D}
UninstallString = "%System%\ShellExt\CNTR.EXE -u"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
{86C43BC7-2319-4322-88FF-9FC402B08B4D}
Date = "{random values}"

HKEY_CURRENT_USER\Software\Freeware\
{FFB51760-344E-4FFB-BFFF-4B18C7AC1D63}
Properties = "{random values}"

HKEY_CURRENT_USER\Software\Freeware\
{FFB51760-344E-4FFB-BFFF-4B18C7AC1D63}\{86C43BC7-2319-4322-88FF-9FC402B08B4D}\Book\
3202
Params = "{random characters}"

HKEY_CURRENT_USER\Software\Freeware\
{FFB51760-344E-4FFB-BFFF-4B18C7AC1D63}\{86C43BC7-2319-4322-88FF-9FC402B08B4D}
LastID = "3202"

It deletes the following registry keys:

HKEY_LOCAL_MACHINE\Software\Microsoft\
Internet Explorer\Extensions\{FFB51760-344E-4FFB-BFFF-4B18C7AC1D63}

Dropping Routine

This Trojan drops the following files:

  • $$del.bat

Other Details

This Trojan deletes itself after execution.

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.300

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

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\Windows\CurrentVersion\Uninstall
    • {86C43BC7-2319-4322-88FF-9FC402B08B4D}
  • In HKEY_CURRENT_USER\Software\Freeware
    • {FFB51760-344E-4FFB-BFFF-4B18C7AC1D63}
  • In HKEY_CURRENT_USER\Software\Freeware\{FFB51760-344E-4FFB-BFFF-4B18C7AC1D63}\{86C43BC7-2319-4322-88FF-9FC402B08B4D}\Book
    • 3202

Step 3

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\Uninstall\{86C43BC7-2319-4322-88FF-9FC402B08B4D}
    • DisplayName = "exdialer"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\{86C43BC7-2319-4322-88FF-9FC402B08B4D}
    • UninstallString = "%System%\ShellExt\CNTR.EXE -u"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\{86C43BC7-2319-4322-88FF-9FC402B08B4D}
    • Date = "{random values}"
  • In HKEY_CURRENT_USER\Software\Freeware\{FFB51760-344E-4FFB-BFFF-4B18C7AC1D63}
    • Properties = "{random values}"
  • In HKEY_CURRENT_USER\Software\Freeware\{FFB51760-344E-4FFB-BFFF-4B18C7AC1D63}\{86C43BC7-2319-4322-88FF-9FC402B08B4D}\Book\3202
    • Params = "{random characters}"
  • In HKEY_CURRENT_USER\Software\Freeware\{FFB51760-344E-4FFB-BFFF-4B18C7AC1D63}\{86C43BC7-2319-4322-88FF-9FC402B08B4D}
    • LastID = "3202"

Step 4

Search and delete this file

[ Learn More ]
There may be some 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.
  • del.bat
del.bat
  • In the Look In drop-down list, select My Computer then press Enter.
  • Once located, select the file then press SHIFT+DELETE to delete it.

    • • For Windows Vista and Windows 7 users:

    1. Click Start>Computer.
    2. In the Search input box, type the following:
      • del.bat
    3. Once located, select the file then press SHIFT+DELETE to delete it.
      *Note: Read the following Microsoft page if these steps do not work on Windows 7.

    Step 5

    Scan your computer with your Trend Micro product to delete files detected as TROJ_DELF.IHI. 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 this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.

    • %System Root%\del.bat
    • %System%\ShellExt\CNTR.EXE
    • %System%\del.bat

    Step 7

    Restore these deleted registry keys/values from backup

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

    • In HKEY_LOCAL_MACHINE\Software\Microsoft\Internet Explorer\Extensions
      • {FFB51760-344E-4FFB-BFFF-4B18C7AC1D63}


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