Modified by: Kathleen Notario
ALIASES:

TrojanDownloader:Win32/Unruy.C (Microsoft); Backdoor.Trojan (Symantec)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • 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.

  TECHNICAL DETAILS

File Size: 30,720 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 22 Apr 2010

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 files:

  • %Windows%\Tasks\At1.job
  • %Windows%\Tasks\At2.job
  • %Windows%\Tasks\At3.job
  • %Windows%\Tasks\At4.job
  • %Windows%\Tasks\At5.job
  • %Windows%\Tasks\At6.job
  • %Windows%\Tasks\At7.job
  • %Windows%\Tasks\At8.job
  • %Windows%\Tasks\At9.job
  • %Windows%\Tasks\At10.job
  • %Windows%\Tasks\At11.job
  • %Windows%\Tasks\At12.job
  • %Windows%\Tasks\At13.job
  • %Windows%\Tasks\At14.job
  • %Windows%\Tasks\At15.job
  • %Windows%\Tasks\At16.job
  • %Windows%\Tasks\At17.job
  • %Windows%\Tasks\At18.job
  • %Windows%\Tasks\At19.job
  • %Windows%\Tasks\At20.job
  • %Windows%\Tasks\At21.job
  • %Windows%\Tasks\At22.job
  • %Windows%\Tasks\At23.job
  • %Windows%\Tasks\At24.job

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

It drops the following copies of itself into the affected system:

  • %Current%\alcmtr.exe
  • %Current%\rthdcpl.exe
  • %User Temp%\wmpscfgs.exe
  • %Program Files%\Internet Explorer\js.mui
  • %Program Files%\Internet Explorer\wmpscfgs.exe

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.. %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).)

Other System Modifications

This Trojan adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer\Main
Enable Browser Extensions = "yes"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Schedule
AtTaskMaxHours = "48"

Other Details

This Trojan connects to the following possibly malicious URL:

  • www.{BLOCKED}ertalkz.com

  SOLUTION

Minimum Scan Engine: 9.200
FIRST VSAPI PATTERN FILE: 7.120.04
FIRST VSAPI PATTERN DATE: 22 Apr 2010
VSAPI OPR PATTERN File: 7.121.00
VSAPI OPR PATTERN Date: 23 Apr 2010

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 terminate files detected as TROJ_KRAP.SMPE

[ Learn More ]
  1. Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
  2. If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
  3. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

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\Internet Explorer\Main
    • Enable Browser Extensions = "yes"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Schedule
    • AtTaskMaxHours = "48"

Step 4

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.  
  • %Windows%\Tasks\At1.job
  • %Windows%\Tasks\At2.job
  • %Windows%\Tasks\At3.job
  • %Windows%\Tasks\At4.job
  • %Windows%\Tasks\At5.job
  • %Windows%\Tasks\At6.job
  • %Windows%\Tasks\At7.job
  • %Windows%\Tasks\At8.job
  • %Windows%\Tasks\At9.job
  • %Windows%\Tasks\At10.job
  • %Windows%\Tasks\At11.job
  • %Windows%\Tasks\At12.job
  • %Windows%\Tasks\At13.job
  • %Windows%\Tasks\At14.job
  • %Windows%\Tasks\At15.job
  • %Windows%\Tasks\At16.job
  • %Windows%\Tasks\At17.job
  • %Windows%\Tasks\At18.job
  • %Windows%\Tasks\At19.job
  • %Windows%\Tasks\At20.job
  • %Windows%\Tasks\At21.job
  • %Windows%\Tasks\At22.job
  • %Windows%\Tasks\At23.job
  • %Windows%\Tasks\At24.job

Step 5

Scan your computer with your Trend Micro product to delete files detected as TROJ_KRAP.SMPE. 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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