Analysis by: Mark Joseph Manahan
ALIASES:

Trojan.Win32.Upof (Ikarus), PAK:UPX, Trojan.Win32.Madi.a (Kaspersky), Trojan.Upof.c (VBA32), W32/Upof.C!tr (Fortinet)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • 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.

  TECHNICAL DETAILS

File Size: 971,776 bytes
File Type: EXE
File Compression: UPX
Memory Resident: Yes
Initial Samples Received Date: 21 Nov 2012

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 adds the following folders:

  • %User Profile%\UpBackup

(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.)

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

  • %User Profile%\UpBackup\UpdateOffice.exe
  • %User Profile%\PrintHood\UpdateOffice.exe

(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.)

Autostart Technique

This Trojan modifies the following registry entry(ies) to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
User Shell Folders
Startup = "%User Profile%\UpBackup"

(Note: The default value data of the said registry entry is "%User Startup%".)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Shell Folders
Startup = "%User Profile%\UpBackup"

(Note: The default value data of the said registry entry is "%User Startup%".)

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://{BLOCKED}il.in/ASLK/khaki/Abi/UUUU.htm

It drops the following file(s)/component(s):

  • %User Profile\PrintHood\{10 random alphanumeric char}.dll
  • %User Profile\PrintHood\{10 random alphanumeric char}.PRI
  • %User Profile\PrintHood\~{20 random alphanumeric char}.tmp
  • %User Profile\PrintHood\SHK.dll
  • %User Profile\PrintHood\SIK.dll
  • %User Profile\PrintHood\FIE.dll
  • %User Profile\PrintHood\BIE.dll
  • %User Profile\PrintHood\Roze.dll
  • %User Profile\PrintHood\xdat.dll
  • %User Profile\PrintHood\mahdi.txt
  • %User Profile\Template\nam.dll
  • %User Profile\PrintHood\pangtip.bat
  • %User Profile\PrintHood\UPDATE~1.EXE.pxkm
  • %User Profile\PrintHood\100.bat
  • %User Profile\PrintHood\{malware fiename}.pdf

  SOLUTION

Minimum Scan Engine: 9.300
FIRST VSAPI PATTERN FILE: 9.540.05
FIRST VSAPI PATTERN DATE: 21 Nov 2012
VSAPI OPR PATTERN File: 9.541.00

Step 1

For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.

Step 2

Identify and terminate files detected as TROJ_MADI.AA

[ Learn More ]
  1. 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.
  2. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

Step 3

Restore this modified registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

 
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders
    • From: Startup = "%User Profile%\UpBackup"
      To: Startup = "%User Startup%"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\User Shell Folders
    • From: Startup = "%User Profile%\UpBackup"
      To: Startup = "%User Startup%"

Step 4

Search and delete this folder

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • %User Profile%\UpBackup

Step 5

Search and delete these files

[ Learn More ]
There may be some component 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 Profile\PrintHood\{10 random alphanumeric char}.dll
  • %User Profile\PrintHood\{10 random alphanumeric char}.PRI
  • %User Profile\PrintHood\~{20 random alphanumeric char}.tmp
  • %User Profile\PrintHood\SHK.dll
  • %User Profile\PrintHood\SIK.dll
  • %User Profile\PrintHood\FIE.dll
  • %User Profile\PrintHood\BIE.dll
  • %User Profile\PrintHood\Roze.dll
  • %User Profile\PrintHood\xdat.dll
  • %User Profile\PrintHood\mahdi.txt
  • %User Profile\Template\nam.dll
  • %User Profile\PrintHood\pangtip.bat
  • %User Profile\PrintHood\UPDATE~1.EXE.pxkm
  • %User Profile\PrintHood\100.bat
  • %User Profile\PrintHood\{malware fiename}.pdf

Step 6

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