Analysis by: Kathleen Notario
 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

This Trojan may be dropped by other malware.

  TECHNICAL DETAILS

File Size: 11,648 bytes
File Type: SYS
Memory Resident: Yes
Initial Samples Received Date: 26 Jan 2012

Arrival Details

This Trojan may be dropped by the following malware:

  • TROJ_DLOAD.QYUA

Autostart Technique

This Trojan registers itself as a system service to ensure its automatic execution at every system startup by adding the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Com32
ImagePath = "%System%\drivers\com32.sys"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Com32
Type = "1"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Com32
Start = "1"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Com32
ErrorControl = "1"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Com32
DisplayName = "Com32"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\FileDisk
ImagePath = "%System%\FileDisk.sys"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\FileDisk
Type = "1"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\FileDisk
Start = "1"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\FileDisk
ErrorControl = "1"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\FileDisk
DisplayName = "FileDisk"

Rootkit Capabilities

This Trojan is used by other malware for its rootkit functionalities.

  SOLUTION

Minimum Scan Engine: 9.200
FIRST VSAPI PATTERN FILE: currently processing

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

Remove the malware/grayware file that dropped/downloaded RTKT_MDIEXP.QYUA

    • TROJ_DLOAD.QYUA

Step 3

Restart in Safe Mode

[ Learn More ]

Step 4

Delete this registry key

[ 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\SYSTEM\CurrentControlSet\Services
    • Com32
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
    • FileDisk

Step 5

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