WORM_RIMECUD.L

February 23, 2011
 Analysis by: Christopher Daniel So
 ALIASES:

Trojan:Win32/Rimecud.A (Microsoft), Mal/Palevo-A (Sophos), Trojan.Win32.Rimecud.d (Sunbelt)

 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 arrives via removable drives.

It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

It executes the files it drops, prompting the affected system to exhibit the malicious routines they contain.

  TECHNICAL DETAILS

File Size:

109,568 bytes

File Type:

PE

Memory Resident:

No

Initial Samples Received Date:

22 Dec 2010

Arrival Details

This worm arrives via removable drives.

Propagation

This worm drops the following copy(ies) of itself in all removable drives:

  • {drive letter}:\ODUZIMAS\midah.exe

It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

The said .INF file contains the following strings:

{random characters}
[autorun]
shell\Install\command=ODUZIMAS\midah.exe
shell\open\command=ODUZIMAS\midah.exe
shell\explore\command=ODUZIMAS\midah.exe
Shell\open\command=ODUZIMAS\midah.exe
useautoplay=1
shellexecute=ODUZIMAS\midah.exe
open=ODUZIMAS\midah.exe
action=Open folder to view files
icon=shell32.dll,4

Dropping Routine

This worm drops the following files:

  • %Application Data%\nsvb.exe - detected as WORM_RIMECUD.MB

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Windows\Profiles\{user name}\Application Data on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Application Data on Windows NT, and C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, XP, and Server 2003.)

It executes the files it drops, prompting the affected system to exhibit the malicious routines they contain.

  SOLUTION

Minimum Scan Engine:

8.900

VSAPI OPR PATTERN File:

7.740.06

VSAPI OPR PATTERN Date:

01 Jan 2011

Step 1

For Windows ME and XP users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.

Step 2

Remove malware files dropped/downloaded by WORM_RIMECUD.L

Step 3

Search and delete AUTORUN.INF files created by WORM_RIMECUD.L that contain these strings

[ Learn More ]
{random characters}
[autorun]
shell\Install\command=ODUZIMAS\midah.exe
shell\open\command=ODUZIMAS\midah.exe
shell\explore\command=ODUZIMAS\midah.exe
Shell\open\command=ODUZIMAS\midah.exe
useautoplay=1
shellexecute=ODUZIMAS\midah.exe
open=ODUZIMAS\midah.exe
action=Open folder to view files
icon=shell32.dll,4

Step 4

Scan your computer with your Trend Micro product to delete files detected as WORM_RIMECUD.L 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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