Analysis by: Michael Cabel
 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: No

  • 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 executes then deletes itself afterward.

It modifies the Internet Explorer Zone Settings.

  TECHNICAL DETAILS

File Size: 158,208 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 20 Jun 2011
Payload: Drops files

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 non-malicious file:

  • %Temp%\{Random File Name}.exe

(Note: %Temp% is the Windows Temporary folder, which is usually C:\Windows\Temp or C:\WINNT\Temp.)

It executes then deletes itself afterward.

Other System Modifications

This worm adds the following registry entries as part of its installation routine:

HKEY_USERS\.DEFAULT\Software\
Microsoft\Internet Explorer\PhishingFilter
EnabledV8 = "0"

HKEY_USERS\.DEFAULT\Software\
Microsoft\Internet Explorer\PhishingFilter
ShownServiceDownBalloon = "0"

HKEY_USERS\.DEFAULT\Software\
Microsoft\Internet Explorer\Recovery
ClearBrowsingHistoryOnExit = "0"

HKEY_USERS\.DEFAULT\Software\
Microsoft\Windows\CurrentVersion\
Internet Settings
EnableHttp1_1 = "1"

HKEY_USERS\.DEFAULT\Software\
Microsoft\Windows\CurrentVersion\
Internet Settings
ProxyHttp1.1 = "1"

HKEY_USERS\.DEFAULT\Software\
Microsoft\Windows\CurrentVersion\
Internet Settings
WarnOnPost = "hex:00,00,00,00,"

HKEY_USERS\.DEFAULT\Software\
Microsoft\Windows\CurrentVersion\
Internet Settings
WarnOnPostRedirect = "0"

HKEY_USERS\.DEFAULT\Software\
Microsoft\Windows\CurrentVersion\
Internet Settings
WarnOnIntranet = "0"

HKEY_USERS\.DEFAULT\Software\
Microsoft\Windows\CurrentVersion\
Internet Settings
GlobalUserOffline = "0"

Propagation

This worm sends copies of itself to target recipients using the following instant-messaging (IM) applications:

  • Windows Live Messenger
  • MSN Messenger

Web Browser Home Page and Search Page Modification

This worm modifies the Internet Explorer Zone Settings.

  SOLUTION

Minimum Scan Engine: 8.900
FIRST VSAPI PATTERN FILE: 8.236.06
FIRST VSAPI PATTERN DATE: 20 Jun 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_MAZAFAKA.A

Step 3

Terminate a process file/s detected as WORM_MAZAFAKA.A

[ Learn More ]

*Note: If the detected file/s is/are not displayed in theWindows Task Manager, continue doing the next steps.

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_USERS\.DEFAULT\Software\Microsoft\Internet Explorer\PhishingFilter
    • EnabledV8 = "0"
  • In HKEY_USERS\.DEFAULT\Software\Microsoft\Internet Explorer\PhishingFilter
    • ShownServiceDownBalloon = "0"
  • In HKEY_USERS\.DEFAULT\Software\Microsoft\Internet Explorer\Recovery
    • ClearBrowsingHistoryOnExit = "0"
  • In HKEY_USERS\.DEFAULT\Software\Microsoft\Windows\CurrentVersion\Internet Settings
    • EnableHttp1_1 = "1"
  • In HKEY_USERS\.DEFAULT\Software\Microsoft\Windows\CurrentVersion\Internet Settings
    • ProxyHttp1.1 = "1"
  • In HKEY_USERS\.DEFAULT\Software\Microsoft\Windows\CurrentVersion\Internet Settings
    • WarnOnPost = "hex:00,00,00,00,"
  • In HKEY_USERS\.DEFAULT\Software\Microsoft\Windows\CurrentVersion\Internet Settings
    • WarnOnPostRedirect = "0"
  • In HKEY_USERS\.DEFAULT\Software\Microsoft\Windows\CurrentVersion\Internet Settings
    • WarnOnIntranet = "0"
  • In HKEY_USERS\.DEFAULT\Software\Microsoft\Windows\CurrentVersion\Internet Settings
    • GlobalUserOffline = "0"

Step 5

Reset Internet security settings

[ Learn More ]

Step 6

Scan your computer with your Trend Micro product to delete files detected as WORM_MAZAFAKA.A. 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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