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WORM_REMICUD.GC

October 09, 2012
 Analysis by: Christopher Daniel So
 ALIASES:

Trojan:Win32/Rimecud.A (Microsoft), W32.Pilleuz (Symantec), W32/Rimecud (McAfee), Trojan.Win32.Pincav.akmx (Kaspersky)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW


This worm 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:

1,490,944 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

07 Apr 2011

Arrival Details

This worm 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 worm drops the following copies of itself into the affected system:

  • %User Profile%\Application Data\vfbu.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 worm adds the following registry entries to enable its automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
Taskman = "%User Profile%\Application Data\vfbu.exe"

Other System Modifications

This worm adds the following registry keys:

HKEY_CLASSES_ROOT\CLSID\{5A8A1D95-22E9-3963-2E06-90BDD094E562}

HKEY_CURRENT_USER\Software\Licenses

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
RFC1156Agent

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
RFC1156Agent
TrapPollTimeMilliSecs = "3a98"

  SOLUTION

Minimum Scan Engine:

9.200

FIRST VSAPI PATTERN FILE:

7.956.09

FIRST VSAPI PATTERN DATE:

07 Apr 2011

VSAPI OPR PATTERN File:

7.957.00

VSAPI OPR PATTERN Date:

08 Apr 2011

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 delete files detected as WORM_REMICUD.GC using either the Startup Disk or Recovery Console

[ Learn More ]

Step 3

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 NT\CurrentVersion\Winlogon
    • Taskman = "%User Profile%\Application Data\vfbu.exe"

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. Before you could do this, you must restart in Safe Mode. For instructions on how to do this, you may refer to this page If the preceding step requires you to restart in safe mode, you may proceed to edit the system registry.

  • In HKEY_CLASSES_ROOT\CLSID
    • {5A8A1D95-22E9-3963-2E06-90BDD094E562}
  • In HKEY_CURRENT_USER\Software
    • Licenses
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft
    • RFC1156Agent

Step 5

Scan your computer with your Trend Micro product to delete files detected as WORM_REMICUD.GC. 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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