TROJ_RENOS.ZL

October 08, 2012
 Analysis by: Erika Bianca Mendoza
 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 may be unknowingly downloaded by a user while visiting malicious websites.

It uses the Windows Task Scheduler to add a scheduled task that executes the copies it drops.

It may create registry entries under a certain registry key.

  TECHNICAL DETAILS

File Size:

121,344 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

21 Apr 2011

Payload:

Connects to URLs/Ips, Downloads files

Arrival Details

This Trojan may be unknowingly downloaded by a user while visiting malicious websites.

Installation

This Trojan drops the following files:

  • %WINDOWS%\Tasks\{BBAEAEAF-1275-40e2-BD6C-BC8F88BD114A}.job

It uses the Windows Task Scheduler to add a scheduled task that executes the copies it drops.

Other System Modifications

This Trojan adds the following registry entries as part of its installation routine:

HKEY_CURRENT_USER\Software\NtWqIVLZEWZU
Cja{number} = "{dword value}"

HKEY_CURRENT_USER\Software\NtWqIVLZEWZU
Cmo1 = "{base64 encoded}"

It may create registry entries under the following registry key:

HKEY_CURRENT_USER\Software\NtWqIVLZEWZU

NOTES:

Other Details
It attempts to access the following URLs to possibly download other malicious files into the system:

  • {BLOCKED}eh.com
  • {BLOCKED}s.com
  • {BLOCKED}nline.com
However the said sites are inaccessible.

  SOLUTION

Minimum Scan Engine:

8.900

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

Terminate the malware/grayware/spyware process:

[ Learn More ]
  • For Windows 98 and ME users, 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.
  • 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.
  • 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 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_CURRENT_USER\Software\
      • NtWqIVLZEWZU

    Step 4

    Search and delete this file

    [ 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\{BBAEAEAF-1275-40e2-BD6C-BC8F88BD114A}.job

    Step 5

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