Analysis by: Mar Philip Elaurza

ALIASES:

Trojan:Win32/Taloc.B (Microsoft)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel: Downloaded from the Internet

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.

It modifies the Internet Explorer Zone Settings.

As of this writing, the said sites are inaccessible.

It deletes the initially executed copy of itself.

  TECHNICAL DETAILS

File Size: 192,168 bytes
File Type: EXE
File Compression: Unknown
Memory Resident: Yes
Initial Samples Received Date: 02 Nov 2015
Payload: Connects to URLs/IPs, Downloads files

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 copies of itself into the affected system and executes them:

  • %Windows%\AppPatch\{8 random letters}\{6 random letters}.exe

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

It drops the following files:

  • %Windows%\AppPatch\{8 random letters}\python27.dll

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

Autostart Technique

This Trojan adds the following registry entries to enable its automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
{8 random letters} = %Windows%\AppPatch\{8 random letters}\{6 random letters}.exe

Other System Modifications

This Trojan modifies the following registry entries:

HKEY_CURRENT_USER\SOFTWARE\Microsoft\
Internet Explorer\Main
Start Page = www.naver.com

(Note: The default value data of the said registry entry is {User Defined Settings}.)

Web Browser Home Page and Search Page Modification

This Trojan modifies the Internet Explorer Zone Settings.

Download Routine

This Trojan accesses the following websites to download files:

  • http://r.qzone.{BLOCKED}q.com/cgi-bin/user/cgi_personal_card?uin=2867523903?=6367

It saves the files it downloads using the following names:

  • %User Temp%\d41d8cd98f00b204e9800998ecf8427e.zip

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

As of this writing, the said sites are inaccessible.

Other Details

This Trojan deletes the initially executed copy of itself

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 11.550.04
FIRST VSAPI PATTERN DATE: 20 Mar 2015
VSAPI OPR PATTERN File: 11.551.00
VSAPI OPR PATTERN Date: 21 Mar 2015

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

Restart in Safe Mode

[ Learn More ]

Step 4

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\Windows\CurrentVersion\Run
    • {8 random letters} = %Windows%\AppPatch\{8 random letters}\{6 random letters}.exe

Step 5

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\Internet Explorer\Main
    • From: Start Page = www.naver.com
      To: Start Page = {User Defined Settings}

Step 6

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.
  • %User Temp%\d41d8cd98f00b204e9800998ecf8427e.zip
  • %Windows%\AppPatch\{8 random letters}\python27.dll

Step 7

Reset Internet security settings

[ Learn More ]

Step 8

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_TALOC.NSW. 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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