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.

It deletes itself after execution.

  TECHNICAL DETAILS

File Size: 69,152 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 05 Sep 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 drops the following copies of itself into the affected system:

  • %User Profile%\ChromeUpdServeis\Microsoft_puhequdiru.exe

(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.)

It creates the following folders:

  • %User Profile%\Application Data\ChromeUpdServeis

(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.)

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
ChromeUpdServeisSystem = "%User Profile%\ChromeUpdServeis\Microsoft_puhequdiru.exe "

Other System Modifications

This Trojan deletes the following files:

  • %User Profile%\ChromeUpdServeis\Microsoft_puhequdiru.exe:Zone.Identifier

(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.)

It adds the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\MINIE

It adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion
ChromeUpdServeisName = "Microsoft_puhequdiru.exe"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion
ChromeUpdServeis32 = "{malware path and file name}"

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
DisableFirstRunCustomize = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
Play_Background_Sounds = "no"

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\MINIE
ShowStatusBar = "1"

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://{BLOCKED}chinka.eu/click/gate.php?{random characters}
  • http://{BLOCKED}chinka.eu/st2/alpha1/cfg9000.txt
  • {BLOCKED}0.1
  • {BLOCKED}7.25
  • {BLOCKED}.197.200

It deletes itself after execution.

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

Restart in Safe Mode

[ Learn More ]

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\Microsoft\Internet Explorer
    • MINIE

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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • ChromeUpdServeisSystem = "%User Profile%\ChromeUpdServeis\Microsoft_puhequdiru.exe "
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion
    • ChromeUpdServeisName = "Microsoft_puhequdiru.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion
    • ChromeUpdServeis32 = "{malware path and file name}"
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
    • DisableFirstRunCustomize = "1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
    • Play_Background_Sounds = "no"
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\MINIE
    • ShowStatusBar = "1"

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.
  • %User Profile%\Application Data\ChromeUpdServeis

Step 6

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_DENISCA.I. 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 this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.

  • %User Profile%\ChromeUpdServeis\Microsoft_puhequdiru.exe:Zone.Identifier


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