Analysis by: Janus Agcaoili
ALIASES:

TrojanDownloader:Win32/Tepoyx.K (Microsoft), Trojan.Win32.Waldek.gbd (Kaspersky)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel: Via email, Downloaded from the Internet

This Trojan may be downloaded from remote sites by other malware.

It does not have any propagation routine.

It does not have any backdoor routine.

It executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.

It connects to certain websites to send and receive information. It gathers information and reports it to its servers.

  TECHNICAL DETAILS

File Size: 87,040 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 11 Mar 2016
Payload: Connects to URLs/IPs

Arrival Details

This Trojan may be downloaded from remote site(s) by the following malware:

  • JS_PAWXNIC.C

Propagation

This Trojan does not have any propagation routine.

Backdoor Routine

This Trojan does not have any backdoor routine.

Download Routine

This Trojan connects to the following website(s) to download and execute a malicious file:

  • https://{BLOCKED}eck.com/se/SoftGetJP.php

It saves the files it downloads using the following names:

  • %User Temp%\{random filename}.exe - varying variants of TROJ_ROVNIX

(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 then executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.

Other Details

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

  • https://{BLOCKED}eck.com/se/SoftCheck.php?id={Product ID}&Ver={version number}&name={executable filename}&ilvl={Security Identifier (SID) Level}

It does the following:

  • It checks for the following processes and Sleeps indefinitely if found running:
    • Python
    • bdagent.exe
    • bdwtxag.exe
  • It will Sleep indefinitely if the OS gives an invalid version or if OS version is equal or lower than “Windows 2000”
  • If run in Windows Vista or above, it will check on the following registry entries:
    • Software\Microsoft\Windows\CurrentVersion\Policies\System\EnableLUA
    • Software\Microsoft\Windows\CurrentVersion\Policies\System\ConsentPromptBehaviorAdmin
  • It installs its own certificate in the system. This certificate will be used for SSL connection to encrypt when downloading malicious binary or reporting to C&C.
  • It also uses SSLv3 to encrypt its data thus even if “GET” request method is used, no readable data can be found.

It gathers the following information and reports it to its servers:

  • Product ID
  • Malware Version number
  • Executable filename of malware
  • Security Identifier (SID) Level

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 12.404.08
FIRST VSAPI PATTERN DATE: 15 Mar 2016
VSAPI OPR PATTERN File: 12.405.00
VSAPI OPR PATTERN Date: 16 Mar 2016

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 TROJ_PAWXNIC.YPOKDT

[ 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

Remove the malware/grayware file that dropped/downloaded TROJ_PAWXNIC.YPOKDT. (Note: Please skip this step if the threat(s) listed below have already been removed.)

     JS_PAWXNIC.C

Step 5

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. %User Temp%\{random filename}.exe

Step 6

Scan your computer with your Trend Micro product to delete files detected as TROJ_PAWXNIC.YPOKDT. 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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