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WORM_RIMECUD.ZZ

June 10, 2013
 Analysis by: Cris Nowell Pantanilla
 ALIASES:

Trojan:Win32/Rimecud.A (Microsoft); W32.Pilleuz!gen30 (Norton), Trojan.Win32.Inject.cbrh (Kaspersky)

 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

Infection Channel:

Via physical/removable drives, Propagates via removable drives


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 does not have any information-stealing capability.

However, as of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size:

144,896 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

02 Mar 2012

Payload:

Connects to URLs/IPs

Arrival Details

This worm arrives via removable drives.

Installation

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

  • %User Profile%\{random}.exe

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

It injects threads into the following normal process(es):

  • SVCHOST.EXE

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%\{random}.exe"

Propagation

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

  • {drive letter}:\sowhat\nonoerm.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:

[autorun]
USEAUTOPLAY=1
shellexecute=sowhat/nonoerm.exe
Shellfqjifkjkqwepfqw
shell\Explore\command=sowhat/nonoerm.exe
shell\Open\command=sowhat/nonoerm.exe
icon=sowhat/nonoerm.exe
open=sowhat//nonoerm.exe
action=0pen folder to view files using Windows Explorer

Information Theft

This worm does not have any information-stealing capability.

Other Details

This worm connects to the following possibly malicious URL:

  • {BLOCKED}de.{BLOCKED}usenumber.com
  • {BLOCKED}ik.{BLOCKED}protection.net.ru
  • {BLOCKED}rld.{BLOCKED}kstudio.ru
  • {BLOCKED}ana.{BLOCKED}lands.su
  • {BLOCKED}tal.{BLOCKED}howerbord.com

However, as of this writing, the said sites are inaccessible.

NOTES:

It is capable of the following:

  • Create and Delete Files
  • List Running processes
  • Create Folders

It does not have rootkit capabilities.

It does not exploit any vulnerability.

  SOLUTION

Minimum Scan Engine:

9.200

FIRST VSAPI PATTERN FILE:

8.812.02

FIRST VSAPI PATTERN DATE:

02 Mar 2012

VSAPI OPR PATTERN File:

8.813.00

VSAPI OPR PATTERN Date:

03 Mar 2012

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 WORM_RIMECUD.ZZ using the 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%\{random}.exe"

Step 4

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

[ Learn More ]


[autorun]
USEAUTOPLAY=1
shellexecute=sowhat/nonoerm.exe
Shellfqjifkjkqwepfqw
shell\Explore\command=sowhat/nonoerm.exe
shell\Open\command=sowhat/nonoerm.exe
icon=sowhat/nonoerm.exe
open=sowhat//nonoerm.exe
action=0pen folder to view files using Windows Explorer

Step 5

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