TROJ_PAWXNIC.B

 Analysis by: Pearl Charlaine Espejo

 ALIASES:

Downloader.Ponik (Symantec); TrojanDropper.Pawxnic.r4 (CAT-QuickHeal); Troj/Pawxnic-C (Sophos)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Via email, Downloaded from the Internet

This Trojan arrives as an attachment to email messages spammed by other malware/grayware or malicious users. It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

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.

  TECHNICAL DETAILS

File Size:

247,744 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

24 Feb 2016

Payload:

Connects to URLs/IPs, Downloads files

Arrival Details

This Trojan arrives as an attachment to email messages spammed by other malware/grayware or malicious users.

It 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 Trojan drops and executes the following files:

  • %User Temp%\lebel_ems2.exe - detected as TROJ_PAWXNIC.B
  • %User Temp%\label_ems.gif

(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.)

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 - detected as 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=0000004&name={executable filename}&ilvl={Security Identifier (SID) Level}

NOTES:

This Trojan checks for the following processes and sleeps indefinitely if found running:

  • Python
  • bdagent.exe
  • bdwtxag.exe

It sleeps indefinitely if the operating system gives an invalid version or if the operating system version is equal or lower than Windows 2000.

If run in Windows Vista or above, it checks 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 is used for SSL connection to encrypt when downloading malicious binary or reporting to its 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:

12.344.05

FIRST VSAPI PATTERN DATE:

15 Feb 2016

VSAPI OPR PATTERN File:

12.345.00

VSAPI OPR PATTERN Date:

16 Feb 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.B

[ 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

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
  • %User Temp%\label_ems.gif

Step 5

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