Analysis by: Janus Agcaoili
ALIASES:

PWS:Win32/Dyzap (Windows), Trojan.Win32.Yakes.mrdq (Kaspersky), Troj/Dridex-GZ (Sophos)

 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 modifies the Internet Explorer Zone Settings.

It connects to certain websites to send and receive information. However, as of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size: 118,784 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 08 Oct 2015
Payload: Connects to URLs/IPs, Collects system 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 adds the following mutexes to ensure that only one of its copies runs at any one time:

  • Global\{random}

It injects threads into the following normal process(es):

  • explorer.exe

Other System Modifications

This spyware adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
CLSID\{GUID}\ShellFolder

Web Browser Home Page and Search Page Modification

This spyware modifies the Internet Explorer Zone Settings.

Information Theft

This spyware gathers the following data:

  • Username
  • Computer Name
  • OS Installation Date
  • Operating System Version
  • List of Installed Programs
    • Display Name
    • Display Version

Other Details

This spyware connects to the following website to send and receive information:

  • {BLOCKED}.{BLOCKED}.187.234:4483
  • {BLOCKED}.{BLOCKED}.226.211:448
  • {BLOCKED}.{BLOCKED}.129.33:4483

It does the following:

  • It writes the configuration file received from its C&C server to a registry in encrypted form:
    • HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\CLSID\{GUID}\ShellFolder
      {random} = "{encrypted configuration}"

However, as of this writing, the said sites are inaccessible.

  SOLUTION

Minimum Scan Engine: 9.750
FIRST VSAPI PATTERN FILE: 11.968.05
FIRST VSAPI PATTERN DATE: 08 Oct 2015
VSAPI OPR PATTERN File: 11.969.00
VSAPI OPR PATTERN Date: 09 Oct 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

Restart in Safe Mode

[ Learn More ]

Step 4

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\Windows\CurrentVersion\Explorer\CLSID
    • {GUID}\ShellFolder

Step 5

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