TROJ_RHINO.AE

October 09, 2012
 Analysis by: Kathleen Notario
 ALIASES:

Trojan.Win32.Agent.rrgn (Kaspersky)

 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

Infection Channel:

Dropped by other malware

This malware connects to a certain site to inform a remote user of its installation and send information such as username and hostname.

This Trojan may be dropped by other malware.

  TECHNICAL DETAILS

File Size:

32,768 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

20 Mar 2012

Payload:

Connects to URLs/IPs

Arrival Details

This Trojan may be dropped by the following malware:

  • JAVA_RHINO.AE

Installation

This Trojan drops the following copies of itself into the affected system:

  • %System%\2019\svchost .exe
  • %User Startup%\wuauclt.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.. %User Startup% is the current user's Startup folder, which is usually C:\Windows\Profiles\{user name}\Start Menu\Programs\Startup on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu\Programs\Startup on Windows NT, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup.)

It creates the following folders:

  • %System%\2019

(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.)

Other System Modifications

This Trojan modifies the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Shell Folders
Startup = "%System%\2019"

(Note: The default value data of the said registry entry is %User Startup%.)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
User Shell Folders
Startup = "%System%\2019"

(Note: The default value data of the said registry entry is %User Startup%.)

NOTES:

It copies the files in the %User Startup% directory to its created folder %System%\2019.

It connects to the following site to inform a remote user of its installation and send information such as username and hostname:

  • {BLOCKED}t.zyns.com

  SOLUTION

Minimum Scan Engine:

9.200

FIRST VSAPI PATTERN FILE:

currently processing

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

Remove the malware/grayware file that dropped/downloaded TROJ_RHINO.AE

     
    • JAVA_RHINO.AE

Step 3

Identify and terminate files detected as TROJ_RHINO.AE

[ Learn More ]
  1. 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.
  2. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

Step 4

Restore this modified 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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders
    • From: Startup = "%System%\2019"
      To: Startup = "%User Startup%"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\User Shell Folders
    • From: Startup = "%System%\2019"
      To: Startup = "%User Startup%"

Step 5

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.
  • %System%\2019

Step 6

Scan your computer with your Trend Micro product to delete files detected as TROJ_RHINO.AE. 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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