Analysis by: Francis Xavier Antazo
 PLATFORM:

Windows

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

  • Threat Type: Spyware

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel: Downloaded from the Internet, Dropped by other malware

This spyware arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It connects to certain websites to send and receive information.

  TECHNICAL DETAILS

File Size: 42,496 bytes
File Type: EXE
Memory Resident: Yes
Payload: Connects to URLs/IPs, Drops files

Arrival Details

This spyware 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 spyware drops the following files:

  • %User Temp%\hInstansePrev734.sys

(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.)

It drops and executes the following files:

  • %All Users Profile%\netconman.exe (to be detected as TSPY_SEDNIT.F)

(Note: %All Users Profile% is the All Users folder, where it usually is C:\Documents and Settings\All Users on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\ProgramData 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.)

It injects codes into the following process(es):

  • iexplore.exe
  • firefox.exe
  • chrome.exe
  • opera.exe
  • browser.exe

Autostart Technique

This spyware creates the following registry entries to enable automatic execution of dropped component at every system startup:

HKEY_CURRENT_USER\Environment
UserInitMprLogonScript = "%All Users Profile%\netconman.exe"

Other System Modifications

This spyware adds the following registry entries:

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Servers
Domain = "{Base 64 encoded CnC domain}"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Servers
Domain = "{Base 64 encoded CnC domain}"

Information Theft

This spyware gathers the following data:

  • volume serial number
  • running processes
  • Hardrive info
  • build id
  • browser injection flag

Other Details

This spyware connects to the following URL(s) to check for an Internet connection:

  • google.com

It connects to the following website to send and receive information:

  • {BLOCKED}oftstoreservice.com
  • {BLOCKED}etlnt.net
  • {BLOCKED}sdefltr.net

It does the following:

  • it downloads its configuration file from its CnC

  SOLUTION

Minimum Scan Engine: 9.800

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_CURRENT_USER\Environment
    • UserInitMprLogonScript = "%All Users Profile%\netconman.exe"

Step 5

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%\hInstansePrev734.sys

Step 6

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