Analysis by: Sammy Chua

ALIASES:

TrojanSpy:MSIL/Golroted.B (Microsoft); Infostealer.Limitail (Symantec); Troj/MSIL-COW (Sophos)

 PLATFORM:

Windows

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

  • Threat Type: Spyware

  • Destructiveness: No

  • Encrypted:

  • 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 retrieves specific information from the affected system.

  TECHNICAL DETAILS

File Size: 735,232 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 06 May 2015
Payload: Steals information

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 non-malicious files:

  • %Application Data%\pidloc.txt --> contains full name and path of malware
  • %User Temp%\holdermail.txt --> deleted afterwards
  • %User Temp%\holderwb.txt --> deleted afterwards
  • %Application Data%\pid.txt --> contains the process id of the malware

(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming 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.. %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 adds the following processes:

  • vbc.exe

Other System Modifications

This spyware adds the following registry keys:

HKEY_LOCAL_MACHINE\Software\Microsoft\
ESENT\Process\{malware name}

HKEY_LOCAL_MACHINE\Software\Microsoft\
ESENT\Process\{malware name}\
DEBUG

It adds the following registry entries:

HKEY_LOCAL_MACHINE\Software\Microsoft\
ESENT\Process\{malware name}\
DEBUG
Trace Level = ""

It modifies the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Hidden = "1"

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

Information Theft

This spyware retrieves the following information from the affected system:

  • Account credentials used in Minecraft, Steam, Mail, and Messenger
  • Keyboard logs
  • Clipboard logs
  • Web browser passwords found in Internet Explorer, Google Chrome, Safari, Mozilla Firefox, Opera, and SeaMonkey
  • Operating System Intel Recovery
    • PC name
    • Local time
    • Installed language
    • Net version
    • Operating system platform
    • Operating system version
    • Internal IP address
    • External IP address
    • Installed anti-malware
    • Installed firewall

Stolen Information

This spyware sends the data it gathers to the following email addresses via SMTP:

  • {BLOCKED}e.uk@mail.ru

Other Details

This spyware connects to the following URL(s) to get the affected system's IP address:

  • http://whatismyipaddress.com/

  SOLUTION

Minimum Scan Engine: 9.750
FIRST VSAPI PATTERN FILE: 11.622.01
FIRST VSAPI PATTERN DATE: 23 Apr 2015
VSAPI OPR PATTERN File: 11.623.00
VSAPI OPR PATTERN Date: 24 Apr 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

Identify and terminate files detected as TSPY_GOLROTED.KD

[ Learn More ]
  1. Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
  2. 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.
  3. 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\Advanced
    • From: Hidden = "1"
      To: Hidden = {User preference}

Step 5

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\Microsoft\ESENT\Process\{malware name}
    • (null)

Step 6

Search and delete these files

[ 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.
  • %Application Data%\pidloc.txt
  • %User Temp%\holdermail.txt
  • %User Temp%\holderwb.txt
  • %Application Data%\pid.txt

Step 7

Scan your computer with your Trend Micro product to delete files detected as TSPY_GOLROTED.KD. 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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