TROJ_UPATRE.SMS

 Analysis by: Sabrina Lei Sioting

 ALIASES:

Win32/TrojanDownloader.Waski.A (Eset), Trojan-Spy.Win32.Zbot.qugi (Kaspersky), TrojanDownloader:Win32/Upatre.A (Microsoft), Downloader.Trojan (Symantec),

 PLATFORM:

Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Spammed via email, Downloaded from the Internet

This malware is involved in a spam campaign that took place on December 2013, as a malicious attachment. Once opened, it connects to certain malicious URLs in order to download and execute malicious files onto the affected system. Affected users may find malicious routines being exhibited on their systems.

To get a one-glance comprehensive view of the behavior of this Trojan, refer to the Threat Diagram shown below.

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

It deletes the initially executed copy of itself.

  TECHNICAL DETAILS

File Size:

18,432 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

04 Dec 2013

Payload:

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 the following copies of itself into the affected system and executes them:

  • %User Temp\budha.exe

Download Routine

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

  • http://{BLOCKED}ame.com/wp-content/uploads/2009/06/pdf.enc
  • http://{BLOCKED}rnia89.com/wp-content/uploads/2013/05/pdf.enc

It saves the files it downloads using the following names:

  • %User Temp%\kilf.exe - TSPY_ZBOT.YDS

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.)

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 deletes the initially executed copy of itself

  SOLUTION

Minimum Scan Engine:

9.300

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

Remove the malware/grayware file dropped/downloaded by TROJ_UPATRE.SMS

    TSPY_ZBOT.SMAA3

Step 3

Restart in Safe Mode

[ Learn More ]

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%\kilf.exe

Step 5

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