WORM_SOHANAD.DU


 ALIASES:

Worm:Win32/Renocide.gen!A (Microsoft), PAK:UPX, ARC:Embedded, [csrcs.au3.tbl.decoded]:Worm.Win32.AutoIt.xl (Kaspersky), W32.Imaut!gen1 (Symantec), Mal/Renocide-A (Sophos), Trojan-Downloader:W32/AutoIt.BI (FSecure), Trojan.Win32.AutoIT.gen (v) (Sunbelt), SPR/AutoIt.Gen (Antivir), Gen:Trojan.Heur.AutoIT.1 (Bitdefender), PUA.Win32.Packer.Upx-53 (Clamav), W32/Renocide.A!worm (Fortinet), Worm.Win32.AutoIt (Ikarus), Win32/Autoit.EP.Gen worm (NOD32), Trj/Autoit.gen (Panda), Trojan.Autoit.F (VBA32)

 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:

Copies itself in all available physical drives, Propagates via removable drives

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 uses the default Windows folder icon to trick users into opening the file. Double-clicking the file executes this malware. It is injected into all running processes to remain memory resident.

It drops copies of itself in all removable and physical drives found in the system. It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

It executes commands from a remote malicious user, effectively compromising the affected system.

  TECHNICAL DETAILS

File Size:

510,226 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

03 Sep 2012

Payload:

Compromises system security, Connects to URLs/IPs, Modifies system registry

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 a copy of itself in the following folders using different file names:

  • %System%\csrcs.exe

(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)

It drops the following component file(s):

  • %System%\autorun.inf - detected as Mal_Otorun1

(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)

It uses the default Windows folder icon to trick users into opening the file. Double-clicking the file executes this malware.

It is injected into all running processes to remain memory resident.

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 entry(ies) to enable its 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

It modifies the following registry entries to hide files with Hidden attributes:

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 copies of itself in all removable and physical drives found in the system.

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 code}
[AutoRun]
;{garbage code}
open=hmegtf.exe
;{garbage code}
shell\open\Command=hmegtf.exe
;{garbage code}
shell\open\Default=1
;{garbage code}
;{garbage code}
shell\explore\Command=hmegtf.exe
;{garbage code}

Backdoor Routine

This worm executes the following commands from a remote malicious user:

  • Connect to a website
  • Connect to an IRC channel to send receive commands
  • Copy ,Download, Execute and Delete files
  • Download malware plugins
  • List Messenger Application contacts
  • List active window titles
  • List and terminate processes
  • Query and manipulate registries
  • Scan for IP addresses within the network
  • Update itself

Download Routine

This worm connects to the following website(s) to download and execute a malicious file:

  • http://ngs.{BLOCKED}m.cx/uhyvd.htm

Other Details

This worm connects to the following URL(s) to get the affected system's IP address:

  • www.whatismyip.com
  • checkip.dyndns.org

  SOLUTION

Minimum Scan Engine:

9.200

FIRST VSAPI PATTERN FILE:

9.370.02

FIRST VSAPI PATTERN DATE:

04 Sep 2012

VSAPI OPR PATTERN File:

9.371.00

VSAPI OPR PATTERN Date:

05 Sep 2012

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

Remove malware/grayware files dropped/downloaded by WORM_SOHANAD.DU

    • Mal_Otorun1

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\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

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

Step 7

Search and delete AUTORUN.INF files created by WORM_SOHANAD.DU that contain these strings

[ Learn More ]
;{garbage code} [AutoRun] ;{garbage code} open=hmegtf.exe ;{garbage code} shell\open\Command=hmegtf.exe ;{garbage code} shell\open\Default=1 ;{garbage code} ;{garbage code} shell\explore\Command=hmegtf.exe ;{garbage code}

Step 8

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