Analysis by: David John Agni

ALIASES:

TrojanDownloader:Win32/Upatre.BC (Microsoft); Backdoor.Win32.Dyreza.aj (Kaspersky); Downloader.Upatre!gen5 (Symantec); Troj/Upatre-KU (Sophos); Trojan.Upatre.AT (BitDefender)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel: Downloaded from the Internet

This Trojan 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.

As of this writing, the said sites are inaccessible.

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

  TECHNICAL DETAILS

File Size: 31,744 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 29 Apr 2015
Payload: Connects to URLs/IPs, Steals information, Downloads files

Arrival Details

This Trojan 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 the following copies of itself into the affected system:

  • %User Temp%\www_search.exe

(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.

Dropping Routine

This Trojan drops the following files:

  • %User Temp%\www_QDF00.txt - contains malware path and file name

(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.)

Download Routine

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

  • https://{BLOCKED}.{BLOCKED}.121.140/tku021.png
  • https://{BLOCKED}.{BLOCKED}.122.31/tku021.png
  • https://{BLOCKED}.{BLOCKED}.138.75/tku021.png
  • https://{BLOCKED}.{BLOCKED}.130.90/tku021.png
  • https://{BLOCKED}.{BLOCKED}.50.65/tku021.png
  • https://{BLOCKED}.{BLOCKED}.2.228/tku021.png
  • https://{BLOCKED}.{BLOCKED}.97.36/tku021.png
  • https://{BLOCKED}.{BLOCKED}.97.71/tku021.png
  • https://{BLOCKED}.{BLOCKED}.2.228/tku021.png

It saves the files it downloads using the following names:

  • %User Temp%\{random filename}.exe

(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.)

As of this writing, the said sites are inaccessible.

Information Theft

This Trojan gathers the following data:

  • Computer name
  • Operating system version
  • Service pack installed

Other Details

This Trojan connects to the following URL(s) to get the affected system's IP address:

  • http://icanhazip.com/

It connects to the following website to send and receive information:

  • http://{BLOCKED}.{BLOCKED}.109.65:{random port}/TKU22/{hostname}/{data}

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

It deletes itself after execution.

  SOLUTION

Minimum Scan Engine: 9.750
VSAPI OPR PATTERN File: 11.627.00
VSAPI OPR PATTERN Date: 24 Apr 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

Search and delete these components

[ Learn More ]
There may be some components 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%\www_QDF00.txt

Step 4

Scan your computer with your Trend Micro product to delete files detected as TROJ_UPATRE.SMNF1. 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.


Did this description help? Tell us how we did.