Analysis by: Sammy Chua
ALIASES:

TrojanDownloader:Win32/Upatre.AY (Microsoft); Trojan-Downloader.Win32.Upatre.vkm (Kaspersky); Downloader.Upatre (Symantec)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

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 deletes the initially executed copy of itself.

  TECHNICAL DETAILS

File Size: 26,112 bytes
File Type: EXE
Initial Samples Received Date: 12 Mar 2015

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 and executes them:

  • %User Temp%\viewtrue.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.)

It drops the following files:

  • %User Temp%\viewEC46.txt
  • %User Temp%\temp15.pdf
  • %User Temp%\{random}.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.)

Other System Modifications

This Trojan adds the following registry entries:

HKLM\SOFTWARE\Microsoft\
Windows NT\CurrentVersion
marker_gjru_fbegrihlgm = "TRUE"

Other Details

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

  • http://checkip.dyndns.org

It connects to the following possibly malicious URL:

  • http://{BLOCKED}.{BLOCKED}.53.78:{random port}/1203uk22/{host name}/0/{os version}/0/EFIBFEFBHGBGM
  • http://{BLOCKED}ch.com/css/klihd.pdf
  • http://{BLOCKED}ealni.com/downloads/NEWS/klihd.pdf
  • http://{BLOCKED}.{BLOCKED}.53.78:{random port}/1203uk22/{host name}/41/7/4/

It deletes the initially executed copy of itself