DIAL_T.A

 Analysis by: Jaime Benigno Reyes

 ALIASES:

Trojan:Win32/Adialer.T (Microsoft); Trojan.Win32.Dialer.t (Kaspersky); SecurityRisk.Downldr (Symantec)

 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:
 INFORMATION EXPOSURE:

  • Threat Type: Dialer

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW


This dialer arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites. It may be manually installed by a user.

It executes then deletes itself afterward.

However, as of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size:

53,248 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

07 Apr 2011

Arrival Details

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

It may be manually installed by a user.

Installation

This dialer drops the following files:

  • %All Users Profile%\Desktop\Dating.lnk (Versions lower than Windows Vista)
  • %All Users Profile%\Desktop\SMS.lnk (Versions lower than Windows Vista)
  • %All Users Profile%\Desktop\XXX.lnk (Versions lower than Windows Vista)
  • %All Users Profile%\Start Menu\Dating.lnk (Versions lower than Windows Vista)
  • %All Users Profile%\Start Menu\SMS.lnk (Versions lower than Windows Vista)
  • %All Users Profile%\Start Menu\XXX.lnk (Versions lower than Windows Vista)
  • %System Root%\Users\Public\Desktop\Dating.lnk (Windows Vista and higher versions)
  • %System Root%\Users\Public\Desktop\Dating.lnk (Windows Vista and higher versions)
  • %System Root%\Users\Public\Desktop\Dating.lnk (Windows Vista and higher versions)
  • %All Users Profile%\Microsoft\Windows\Start Menu\Dating.lnk (Windows Vista and higher versions)
  • %All Users Profile%\Microsoft\Windows\Start Menu\Dating.lnk (Windows Vista and higher versions)
  • %All Users Profile%\Microsoft\Windows\Start Menu\Dating.lnk (Windows Vista and higher versions)
  • %System Root%\delme4.bat - deleted afterwards

(Note: %All Users Profile% is the All Users or Common profile folder, which is C:\Documents and Settings\All Users in Windows 2000, XP, and Server 2003, and C:\ProgramData in Windows Vista and 7.. %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

It executes then deletes itself afterward.

Other Details

This dialer connects to the following possibly malicious URL:

  • http://{BLOCKED}.{BLOCKED}.110.170/ab/cnt/6.asp
  • http://www.{BLOCKED}les.nu/Download/int/smsdial752.exe
  • http://www.{BLOCKED}les.nu/Download/int/dating762.exe
  • http://www.{BLOCKED}les.nu/Download/int/ConnInt5.exe
  • http://www.{BLOCKED}les.nu/Download/int/_ConnectInt5.exe

However, as of this writing, the said sites are inaccessible.

  SOLUTION

Minimum Scan Engine:

9.700

SSAPI PATTERN File:

1.165.00

SSAPI PATTERN Date:

07 Apr 2011

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

Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

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.  
  • %All Users Profile%\Desktop\Dating.lnk (Versions lower than Windows Vista)
  • %All Users Profile%\Desktop\SMS.lnk (Versions lower than Windows Vista)
  • %All Users Profile%\Desktop\XXX.lnk (Versions lower than Windows Vista)
  • %All Users Profile%\Start Menu\Dating.lnk (Versions lower than Windows Vista)
  • %All Users Profile%\Start Menu\SMS.lnk (Versions lower than Windows Vista)
  • %All Users Profile%\Start Menu\XXX.lnk (Versions lower than Windows Vista)
  • %System Root%\Users\Public\Desktop\Dating.lnk (Windows Vista and higher versions)
  • %System Root%\Users\Public\Desktop\Dating.lnk (Windows Vista and higher versions)
  • %System Root%\Users\Public\Desktop\Dating.lnk (Windows Vista and higher versions)
  • %All Users Profile%\Microsoft\Windows\Start Menu\Dating.lnk (Windows Vista and higher versions)
  • %All Users Profile%\Microsoft\Windows\Start Menu\Dating.lnk (Windows Vista and higher versions)
  • %All Users Profile%\Microsoft\Windows\Start Menu\Dating.lnk (Windows Vista and higher versions)

Step 4

Scan your computer with your Trend Micro product to delete files detected as DIAL_T.A. 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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