WORM_PROLACO.SMX

 Analysis by: Christopher Daniel So

 ALIASES:

VirTool:Win32/DelfInject.gen!AC (Microsoft), W32.Ackantta@mm (Symantec), Backdoor-EIG (McAfee)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW


This worm arrives as attachment to mass-mailed email messages.

It executes the files it drops, prompting the affected system to exhibit the malicious routines they contain.

  TECHNICAL DETAILS

File Size:

Varies

File Type:

PE

Memory Resident:

Yes

Initial Samples Received Date:

12 Jan 2011

Arrival Details

This worm arrives as attachment to mass-mailed email messages.

Installation

This worm drops the following copies of itself into the affected system:

  • %System%\{random file name 1}.exe

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
{random key name} = "%System%\{random file name 1}.exe"

Other System Modifications

This worm adds the following registry keys:

HKEY_CURRENT_USER\Software\{random key name}

HKEY_LOCAL_MACHINE\SOFTWARE\{random key name}

It adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer
{random string} = "{current month}"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer
{random string} = "{current day}"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
UACDisableNotify = 1

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
system
EnableLUA = 0

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\ERSvc
FailureActions = {random values}

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\ERSvc
DeleteFlag = 1

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\wscsvc
FailureActions = {random values}

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\wscsvc
DeleteFlag = 1

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\ERSvc
Start = 4

(Note: The default value data of the said registry entry is 2.)

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\wscsvc
Start = 4

(Note: The default value data of the said registry entry is 2.)

It creates the following registry entry(ies) to bypass Windows Firewall:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess|parameters\FirewallPolicy\
StandardProfile\AuthorizedApplications\List
%System%\{random file name 1}.exe = "%System%\{random file name 1}.exe:*:Enabled:Explorer"

Dropping Routine

This worm drops the following files:

  • %System%\{random file name 2}.exe - detected as TROJ_HILOTI.DP or TROJ_DELFIN.G

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

It executes the files it drops, prompting the affected system to exhibit the malicious routines they contain.

  SOLUTION

Minimum Scan Engine:

8.900

VSAPI OPR PATTERN File:

7.767.00

VSAPI OPR PATTERN Date:

14 Jan 2011

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

Remove the malware/grayware file dropped/downloaded by WORM_PROLACO.SMX. (Note: Please skip this step if the threat(s) listed below have already been removed.)

Step 3

Restart in Safe Mode

[ Learn More ]

Step 4

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_CURRENT_USER\Software
    • {random key name}
  • In HKEY_LOCAL_MACHINE\SOFTWARE
    • {random key name}

Step 5

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\Run
    • {random key name}=%System%\{random file name 1}.exe
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer
    • {random string}={current month}
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer
    • {random string}={current day}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
    • UACDisableNotify=1
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\system
    • EnableLUA=0
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\ERSvc
    • FailureActions={random values}
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\ERSvc
    • DeleteFlag=1
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\wscsvc
    • FailureActions={random values}
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\wscsvc
    • DeleteFlag=1
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess|parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
    • %System%\{random file name 1}.exe=%System%\{random file name 1}.exe:*:Enabled:Explorer

Step 6

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_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\ERSvc
    • From: Start=4
      To: Start=2
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\wscsvc
    • From: Start=4
      To: Start=2

Step 7

Restart in normal mode and scan your computer with your Trend Micro product for files detected as WORM_PROLACO.SMX. 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 8

Scan your computer with your Trend Micro product to delete files detected as WORM_PROLACO.SMX. 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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