Analysis by: Ryan Paolo Maglaque

ALIASES:

Trojan-PSW.Win32.Chisburg.agbw(Kaspersky);

 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.

It modifies the Internet Explorer Zone Settings.

  TECHNICAL DETAILS

File Size: 1,456,128 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 14 Feb 2017
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%\cSl8ooxWZ0\cSl8ooxWZ0.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:

  • %User Temp%\aut{Random Hex Values}.tmp -> Deleted afterwards
  • %User Temp%\62xJCIi.A
  • %User Temp%\{10 Random Alphanumeric Characters}.ini -> Deleted afterwards

(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 creates the following folders:

  • %Application Data%\cSl8ooxWZ0\

(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.)

Autostart Technique

This spyware drops the following file(s) in the Windows User Startup folder to enable its automatic execution at every system startup:

  • %User Startup%\cSl8ooxWZ0.eu.url

(Note: %User Startup% is the current user's Startup folder, which is usually C:\Documents and Settings\{user}\Start Menu\Programs\Startup on Windows 2000 and XP, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows Vista, 7, and 8.)

Web Browser Home Page and Search Page Modification

This spyware modifies the Internet Explorer Zone Settings.

Information Theft

This spyware attempts to get stored information such as user names, passwords, and hostnames from the following browsers:

  • Opera
  • Chrome
  • Mozilla Firefox
  • Safari

Stolen Information

This spyware sends the gathered information via HTTP POST to the following URL:

  • http://www.{BLOCKED}agenco.com/deputation/pep/PHP/PHP/index.php?action=add&username={Username}&password={Password}&app={Application}&pcname={Computer Name}&sitename={URL of credentials}

Other Details

This spyware does the following:

  • The dropped .url file contains this specific URL value:
    • file:///%Application Data%\cSl8ooxWZ0\cSl8ooxWZ0.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.)

NOTES:

This spyware steals user names and passwords from the following:

  • FileZilla
  • jDownloader
  • Internet Download Manager
  • Registry, website, or application defined in %User Temp%\{10 Random Alphanumeric Characters}.ini
  • Trillian
  • VPN Credentials

  •   SOLUTION

    Minimum Scan Engine: 9.850
    FIRST VSAPI PATTERN FILE: 13.220.07
    FIRST VSAPI PATTERN DATE: 14 Feb 2017
    VSAPI OPR PATTERN File: 13.221.00
    VSAPI OPR PATTERN Date: 15 Feb 2017

    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

    Search and delete these folders

    [ 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.  
    • %Application Data%\cSl8ooxWZ0\

    Step 4

    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%\62xJCIi.A
    • %User Startup%\cSl8ooxWZ0.eu.url
    • %User Temp%\{10 Random Alphanumeric Characters}.ini
    • %User Temp%\aut{random hex values}.tmp

    Step 5

    Scan your computer with your Trend Micro product to delete files detected as TSPY_CHISBURG.WOKC. 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 6

    Reset Internet security settings

    [ Learn More ]


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