WORM_RIMECUD.VG

October 09, 2012
 Modified by: Michael Cabel
 ALIASES:

VirTool:Win32/CeeInject.gen!AT (Microsoft); W32/Rimecud.bfr!a (McAfee); W32.Pilleuz (Symantec); Trojan.Win32.Buzus.ckem (Kaspersky); Net-Worm.Win32.Kolab.ehp (v) (Sunbelt); Trojan.Generic.2615726 (FSecure)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: No

  • 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.

It creates folders in all physical and 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.

  TECHNICAL DETAILS

File Size:

159,744 bytes

Memory Resident:

Yes

Initial Samples Received Date:

26 Dec 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:

  • %System Root%\RECYCLER\{Random SID}\mwau.exe

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

It creates the following folders:

  • %System Root%\RECYCLER\{Random SID}

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

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 = "%System Root%\RECYCLER\{Random SID}\mwau.exe"

Propagation

This worm creates the following folders in all physical and removable drives:

  • {drive letter}:\Empty

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

  • {drive letter}:\Empty\autorun.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:

;{garbage codes}
;{garbage codes}
[autorun
;{garbage codes}
open=Empty/autorun.exe
;{garbage codes}
action=Open folder to view files using Windows Explorer
;{garbage codes}
shell\open\command=Empty/autorun.exe
;{garbage codes}
shell\explore\command=Empty/autorun.exe
;{garbage codes}
useautoplay=1
;{garbage codes}
:GOTO END

Dropping Routine

This worm drops the following files:

  • %System Root%\RECYCLER\{Random SID}\Desktop.ini

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)