TROJ_MEDFOS.YUT

October 09, 2012
 Analysis by: Lord Alfred Remorin
 Modified by: Jasen Sumalapao
 ALIASES:

Trojan:Win32/Medfos.gen!A (Microsoft), Trojan.Win32.Midhos.lrt (Kaspersky), Medfos.q (NAI), Mal/Midhos-A (Sophos), Gen:Variant.Symmi.261 (Fsecure), Trojan.Win32.Generic!BT (Sunbelt), TR/Medfos.E (Antivir), Gen:Variant.Symmi.261 (Bitdefender), W32/Medfos.ALI!tr (Fortinet), Trojan.Win32.Medfos (Ikarus), a variant of Win32/Medfos.CE trojan (NOD32), Generic (Panda)

 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 may arrive bundled with malware packages as a malware component. 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 exports functions used by other malware. It requires its main component to successfully perform its intended routine.

  TECHNICAL DETAILS

File Size:

158,720 bytes

File Type:

DLL

Memory Resident:

Yes

Initial Samples Received Date:

22 Aug 2012

Arrival Details

This Trojan may arrive bundled with malware packages as a malware component.

It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Autostart Technique

This Trojan adds the following registry entries to enable its automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
{malware file name} = "rundll32.exe "{malware path and file name}",TextureStatus"

Other Details

This Trojan exports functions used by other malware.

It connects to the following possibly malicious URL:

  • 11tbawbta.{BLOCKED}oneetc.com/file/id={Random Value}&rt={Random Value}

It requires its main component to successfully perform its intended routine.

  SOLUTION

Minimum Scan Engine:

9.200

FIRST VSAPI PATTERN FILE:

9.344.02

FIRST VSAPI PATTERN DATE:

23 Aug 2012

VSAPI OPR PATTERN File:

9.345.00

VSAPI OPR PATTERN Date:

24 Aug 2012

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

Scan your computer with your Trend Micro product and note files detected as TROJ_MEDFOS.YUT

Step 3

Restart in Safe Mode

[ Learn More ]

Step 4

Delete this 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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • {malware file name} = "rundll32.exe "{malware path and file name}",TextureStatus"

Step 5

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_MEDFOS.YUT. 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.