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TSPY_KRONOS.B

December 01, 2016
 Analysis by: John Kevin Sanchez
 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:

Dropped by other malware, Downloaded from the Internet


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.

  TECHNICAL DETAILS

File Size:

406,882 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

18 Nov 2016

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 copies of itself into the affected system:

  • %Application Data%\Microsoft\{GUID}\{random 8 alphanumeric characters}.exe

(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.)

It drops the following files:

  • %Application Data%\Mozilla\Firefox\Profiles\{All Folders}\user.js

(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.)

It adds the following processes:

  • %System%\svchost.exe

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

It injects itself into the following processes as part of its memory residency routine:

  • added svchost.exe
  • all running processes except chrome.exe and explorer.exe

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
{random 8 alphanumeric characters} = %Application Data%\Microsoft\{GUID}\{random 8 alphanumeric characters}.exe

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Run
{random 8 alphanumeric characters} = %Application Data%\Microsoft\{GUID}\{random 8 alphanumeric characters}.exe

Other System Modifications

This spyware adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion
{random 8 alphanumeric characters} = {GUID}

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion
{random 8 alphanumeric characters} = {GUID}

Other Details

This spyware does the following:

  • It lowers the security of Mozilla Firefox browser.
  • It checks for existence of virtual environment.
  • It has the capability of stealing credentials from browsers.

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

12.906.02

FIRST VSAPI PATTERN DATE:

18 Nov 2016

VSAPI OPR PATTERN File:

12.907.00

VSAPI OPR PATTERN Date:

19 Nov 2016

Step 1

Trend Micro products with the XGen technology detect this malware as

[ Learn More ]
  • TROJ.WIN32.TRX.XXPE0007

Step 2

Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.

Step 3

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 4

Restart in Safe Mode

[ Learn More ]

Step 5

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
    • {random 8 alphanumeric characters} = %Application Data%\Microsoft\{GUID}\{random 8 alphanumeric characters}.exe
  • In HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
    • {random 8 alphanumeric characters} = %Application Data%\Microsoft\{GUID}\{random 8 alphanumeric characters}.exe
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion
    • {random 8 alphanumeric characters} = {GUID}
  • In HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion
    • {random 8 alphanumeric characters} = {GUID}

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.
  • %Application Data%\Mozilla\Firefox\Profiles\{All Folders}\user.js

Step 7

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


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