Modified by: Erika Bianca Mendoza

 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 unknowingly downloaded by a user while visiting malicious websites.

It also has rootkit capabilities, which enables it to hide its processes and files from the user.

  TECHNICAL DETAILS

File Size: 258,048 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 22 Nov 2011

Arrival Details

This Trojan may be unknowingly downloaded by a user while visiting malicious websites.

Installation

This Trojan drops the following files:

  • %Application Data%\8c0f0459\@
  • %Application Data%\8c0f0459\X

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

It creates the following folders:

  • %Application Data%\8c0f0459
  • %Application Data%\8c0f0459\U
  • %Windows%\1493438348

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

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\8c0f0459
ImagePath = "\systemroot\1493438348:1945172902.exe"

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows NT\CurrentVersion\Winlogon
Shell = "%Application Data%\8c0f0459\X"

Other System Modifications

This Trojan adds the following registry keys as part of its installation routine:

HKEY_CLASSES_ROOT\Interface\{b1041c7f-46ea-d87c-4a51-abba7b80f3da}

It also creates the following registry entry(ies) as part of its installation routine:

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{b1041c7f-46ea-d87c-4a51-abba7b80f3da}
cid = "{hex values}"

HKEY_CURRENT_USER\Software\8c0f0459
u = "dword:00000075"

HKEY_CURRENT_USER\Software\8c0f0459
id = "{hex values}"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{b1041c7f-46ea-d87c-4a51-abba7b80f3da}
u = "dword:00000075"

Rootkit Capabilities

This Trojan also has rootkit capabilities, which enables it to hide its processes and files from the user.

  SOLUTION

Minimum Scan Engine: 9.200
FIRST VSAPI PATTERN FILE: 8.592.04
FIRST VSAPI PATTERN DATE: 22 Nov 2011
VSAPI OPR PATTERN File: 8.593.00
VSAPI OPR PATTERN Date: 23 Nov 2011

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

Identify and delete files detected as RTKT_ZACESS.SMAE using the Recovery Console

[ Learn More ]

Step 3

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_CLASSES_ROOT\Interface
    • {b1041c7f-46ea-d87c-4a51-abba7b80f3da}
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
    • 8c0f0459

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_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Winlogon
    • Shell = "%Application Data%\8c0f0459\X"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{b1041c7f-46ea-d87c-4a51-abba7b80f3da}
    • cid = "{hex values}"
  • In HKEY_CURRENT_USER\Software\8c0f0459
    • u = "dword:00000075"
  • In HKEY_CURRENT_USER\Software\8c0f0459
    • id = "{hex values}"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{b1041c7f-46ea-d87c-4a51-abba7b80f3da}
    • u = "dword:00000075"

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.
  • %Application Data%\8c0f0459\@
  • %Application Data%\8c0f0459\X

Step 6

Search and delete these folders

[ 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.
  • %Application Data%\8c0f0459
  • %Windows%\1493438348

Step 7

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