WORM_RIMECUD.AJB

 Analysis by: Rika Joi Gregorio

 ALIASES:

Trojan:Win32/Rimecud.A (Microsoft); W32/Rimecud.gen.br (McAfee); Trojan.Gen.2 (Symantec); Trojan.Win32.Generic!BT (Sunbelt)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Downloaded from the Internet, Dropped by other malware


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.

  TECHNICAL DETAILS

File Size:

92,672 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

09 Nov 2012

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:

  • %User Profile%\aegvvp.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.)

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

  • {drive letter}:\windows\works.exe

The said .INF file contains the following strings:

[autorun]
USEAUTOPLAY=1
shellexcute=windows/works.exe
Shellasia
shell\Explore\command=windows/works.exe
shell\Open\command=windows/works.exe
icon=windows/works.exe
open=windows/works.exe
action=0pen folder to view files using Windows Explorer

Other Details

This worm connects to the following possibly malicious URL:

  • {BLOCKED}e.{BLOCKED}usenumber.com
  • {BLOCKED}k.{BLOCKED}-protection.net.ru
  • {BLOCKED}d.{BLOCKED}udio.ru
  • {BLOCKED}a.{BLOCKED}nds.su

  SOLUTION

Minimum Scan Engine:

9.300

FIRST VSAPI PATTERN FILE:

9.514.05

FIRST VSAPI PATTERN DATE:

23 Aug 2011

VSAPI OPR PATTERN File:

9.515.00

VSAPI OPR PATTERN Date:

24 Aug 2011

Step 1

For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.

Step 2

Scan your computer with your Trend Micro product and note files detected as WORM_RIMECUD.AJB

Step 3

Restart in Safe Mode

[ Learn More ]

Step 4

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%\aegvvp.exe"

Step 5

Search and delete these files

[ Learn More ]
There may be some component files 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 Profile%\aegvvp.exe

Step 6

Search and delete this folder

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.  
  • {drive letter}:\windows

Step 7

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

[ Learn More ]

[autorun]

USEAUTOPLAY=1

shellexcute=windows/works.exe

Shellasia

shell\Explore\command=windows/works.exe

shell\Open\command=windows/works.exe

icon=windows/works.exe

open=windows/works.exe

action=0pen folder to view files using Windows Explorer

Step 8

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

Step 9

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