Analysis by: Rika Joi Gregorio

ALIASES:

Worm:Win32/Renocide.gen!A(Microsoft), W32.Harakit(Symantec), W32/Klone.BJ(Fortinet),

 PLATFORM:

Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted:

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

It deletes itself after execution.

  TECHNICAL DETAILS

File Size: 502,958 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 05 Mar 2014

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 and executes them:

  • %System%\csrcs.exe

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)

Autostart Technique

This worm adds the following registry entries to enable its automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Explorer\Run
csrcs = "%System%\csrcs.exe"

It modifies the following registry entries to ensure it automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
Shell = "Explorer.exe csrcs.exe"

(Note: The default value data of the said registry entry is Explorer.exe.)

Other System Modifications

This worm adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
DRM\amty

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Explorer

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Explorer\Run

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
DRM\amty
ilop = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
DRM\amty
fix = ""

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
DRM\amty
fix1 = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings
GlobalUserOffline = "0"

It modifies the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Hidden = "2"

(Note: The default value data of the said registry entry is 1.)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
SuperHidden = "0"

(Note: The default value data of the said registry entry is 1.)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
ShowSuperHidden = "0"

(Note: The default value data of the said registry entry is 1.)

Propagation

This worm 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
[AutoRun]
;garbage codes
open=mcwpok.exe
;garbage codes
shell\open\Command=mcwpok.exe
;garbage codes
shell\open\Default=1
;garbage codes
;garbage codes
shell\explore\Command=mcwpok.exe
;garbage codes

Other Details

This worm connects to the following possibly malicious URL:

  • http://www.{BLOCKED}myip.com/automation/n09230945.asp
  • http://{BLOCKED}ip.dyndns.org/?rnd1=5842.07003541314&rnd2=32391.7030609541
  • http://{BLOCKED}u.akakapatama.com:2547/Now/fall.gif
  • http://{BLOCKED}u.or.tp:2547/Now/out.gif
  • http://{BLOCKED}dro.or.tp:2547/Now/fast.gif

It deletes itself after execution.

  SOLUTION

Minimum Scan Engine: 9.300
FIRST VSAPI PATTERN FILE: 7.514.11
FIRST VSAPI PATTERN DATE: 05 Oct 2010
VSAPI OPR PATTERN File: 7.515.00
VSAPI OPR PATTERN Date: 06 Oct 2010

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_UTOTI.SMA using either the Startup Disk or Recovery Console

[ Learn More ]

Step 3

Delete this registry key

[ 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\DRM
    • amty
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies
    • Explorer

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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings
    • GlobalUserOffline = "0"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\Explorer\Run
    • csrcs = "%System%\csrcs.exe"

Step 5

Restore this modified 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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • From: Hidden = "2"
      To: Hidden = 1
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • From: SuperHidden = "0"
      To: SuperHidden = 1
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • From: ShowSuperHidden = "0"
      To: ShowSuperHidden = 1
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
    • From: Shell = "Explorer.exe csrcs.exe"
      To: Shell = Explorer.exe

Step 6

Search and delete AUTORUN.INF files created by WORM_UTOTI.SMA that contain these strings

[ Learn More ]


;garbage codes
[AutoRun]
;garbage codes
open=mcwpok.exe
;garbage codes
shell\open\Command=mcwpok.exe
;garbage codes
shell\open\Default=1
;garbage codes
;garbage codes
shell\explore\Command=mcwpok.exe
;garbage codes

Step 7

Scan your computer with your Trend Micro product to delete files detected as WORM_UTOTI.SMA. 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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