WORM_RIMECUD.DI

 Analysis by: Sabrina Lei Sioting

 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 by connecting affected removable drives to a system. It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

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:

88,064 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

22 Nov 2011

Arrival Details

This worm arrives by connecting affected removable drives to a system.

It 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%\aegvvp.exe
  • %System Root%\RECYCLER\S-1-5-21-1614895754-436374069-682003330-1003\Dc1.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.. %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

It adds the following processes:

  • 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%\aegvvp.exe"

Propagation

This worm creates the following folders in all removable drives:

  • ultimate

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

  • ultimate\window.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
shellexcute=ultimate/window.exe
Shelldisc
shell\Explore\command=ultimate/window.exe
shell\Open\command=ultimate/window.exe
icon=ultimate/window.exe
open=ultimate/window.exe
action=0pen folder to view files using Windows Explorer