WORM_RIMECUD.SMC

November 26, 2013
 Analysis by: Christopher Daniel So
 ALIASES:

Worm:Win32/Rimecud.B (Microsoft), W32/Rimecud.gen.l (McAfee), P2P-Worm.Win32.Palevo.bivw (Kaspersky), W32/Injector.P!tr (Fortinet), W32/Palevo.FS (FProt)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

This worm may be downloaded from remote sites by other malware.

  TECHNICAL DETAILS

File Size:

61,440 bytes

File Type:

PE

Memory Resident:

Yes

Initial Samples Received Date:

30 Nov 2010

Arrival Details

This worm may be downloaded from remote site(s) by the following malware:

  • WORM_RIMECUD.ZB

It may be downloaded from the following remote sites:

  • http://{BLOCKED}pgirl.com/ms0593.exe

Installation

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

  • %System%\umdmgr.exe

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)

Autostart Technique

This worm 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} = "%System%\umdmgr.exe"

Download Routine

This worm connects to the following URL(s) to download its configuration file:

  • http://umx1.{BLOCKED}dult.biz/umxx1.gif

It saves the files it downloads using the following names:

  • %User Temp%\umdmgr.ini

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

Other Details

This worm does the following:

  • It decrypts the downloaded configuration file and saves the decrypted configuration file in %User Temp%\umdmgr.ini_dec. It then connects to the websites specified in the configuration file.

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

  SOLUTION

Minimum Scan Engine:

8.900

VSAPI PATTERN File:

7.712.10

VSAPI PATTERN Date:

20 Dec 2010

VSAPI PATTERN Date:

12/20/2010 12:00:00 AM

FIRST VSAPI PATTERN FILE:

7.670.06

FIRST VSAPI PATTERN DATE:

02 Dec 2010

VSAPI OPR PATTERN File:

7.713.00

VSAPI OPR PATTERN Date:

21 Dec 2010

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

Restart in Safe Mode

[ 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\CurrentVersion\Run
    • {malware file name}=%System%\umdmgr.exe

Step 4

Search and delete these components

[ Learn More ]
There may be some components 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 Temp%\umdmgr.ini
  • %User Temp%\umdmgr.ini_dec

Step 5

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