TROJ_TESYONG.B


 ALIASES:

Trojan:Win32/Tesyong.A (Microsoft); RDN/Generic.dx!dsn (McAfee); Trojan.Win32.Scar.jguf (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt); Trojan horse Packed2_c.BKAD (AVG)

 PLATFORM:

Windows

 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.

  TECHNICAL DETAILS

File Size:

1,028,096 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

05 Jun 2015

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 creates the following folders:

  • %Program Files%\Microsoft TemSysy

(Note: %Program Files% is the Program Files folder, where it usually is C:\Program Files on all Windows operating system versions; C:\Program Files (x86) for 32-bit applications running on Windows 64-bit operating systems.)

Other System Modifications

This Trojan adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{248DD896-BB45-11CF-9ABC-0080C7E7B78D}\Control

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
TypeLib\{248DD890-BB45-11CF-9ABC-0080C7E7B78D}

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
TypeLib\{248DD890-BB45-11CF-9ABC-0080C7E7B78D}\1.0\
0

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{248DD896-BB45-11CF-9ABC-0080C7E7B78D}\InprocServer32
ThreadingModel = "Apartment"

(Note: The default value data of the said registry entry is Apartment.)

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{248DD892-BB45-11CF-9ABC-0080C7E7B78D}\TypeLib
Version = "1.0"

(Note: The default value data of the said registry entry is 1.0.)

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{248DD893-BB45-11CF-9ABC-0080C7E7B78D}\TypeLib
Version = "1.0"

(Note: The default value data of the said registry entry is 1.0.)

It deletes the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{248DD896-BB45-11CF-9ABC-0080C7E7B78D}

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{248DD897-BB45-11CF-9ABC-0080C7E7B78D}

Dropping Routine

This Trojan drops the following files:

  • %System Root%\Kill.bat

(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.)

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.750

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\Classes\CLSID\{248DD896-BB45-11CF-9ABC-0080C7E7B78D}
    • Control
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\TypeLib
    • {248DD890-BB45-11CF-9ABC-0080C7E7B78D}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\TypeLib\{248DD890-BB45-11CF-9ABC-0080C7E7B78D}\1.0
    • 0

Step 3

Restore these modified registry values

[ Learn More ]

Important:Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator's help. You may also check out this Microsoft article first before modifying your computer's registry.

  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{248DD896-BB45-11CF-9ABC-0080C7E7B78D}\InprocServer32
    • From: ThreadingModel = "Apartment"
      To: ThreadingModel = ""Apartment""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{248DD892-BB45-11CF-9ABC-0080C7E7B78D}\TypeLib
    • From: Version = "1.0"
      To: Version = ""1.0""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{248DD893-BB45-11CF-9ABC-0080C7E7B78D}\TypeLib
    • From: Version = "1.0"
      To: Version = ""1.0""

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.
  • %System Root%\Kill.bat

Step 5

Search and delete this folder

[ 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.
  • %Program Files%\Microsoft TemSysy

Step 6

Scan your computer with your Trend Micro product to delete files detected as TROJ_TESYONG.B. 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 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\Classes\CLSID
    • {248DD896-BB45-11CF-9ABC-0080C7E7B78D}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID
    • {248DD897-BB45-11CF-9ABC-0080C7E7B78D}


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