ALIASES:

Backdoor:Win32/Popwin.B (Microsoft); Generic Malware.ja (McAfee); Suspicious.Graybird.1 (Symantec); Worm.Win32.AutoRun.jj (Kaspersky); Backdoor.Win32.Popwin.B (v) (Sunbelt); Worm/Generic3.FWQ (AVG)

 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

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 deletes itself after execution.

  TECHNICAL DETAILS

File Size: 18,432 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 25 Jul 2013

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.

Other System Modifications

This worm deletes the following files:

  • %Windows%\SoftwareDistribution\DataStore\Logs\edbtmp.log

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

It adds the following registry keys:

HKEY_CURRENT_USER\SYSTEM\CurrentControlSet\
Services\EBCF5B90

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\EBCF5B90
Description = "C74F4050"

HKEY_CURRENT_USER\SYSTEM\CurrentControlSet\
Services\EBCF5B90
Description = "C74F4050"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\EBCF5B90
DisplayName = "EBCF5B90"

HKEY_CURRENT_USER\SYSTEM\CurrentControlSet\
Services\EBCF5B90
DisplayName = "EBCF5B90"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\EBCF5B90
ErrorControl = "1"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\EBCF5B90
ImagePath = "%System%\9788BBD0.EXE -k"

HKEY_CURRENT_USER\SYSTEM\CurrentControlSet\
Services\EBCF5B90
ImagePath = "%System%\9788BBD0.EXE -k"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\EBCF5B90
ObjectName = "LocalSystem"

HKEY_CURRENT_USER\SYSTEM\CurrentControlSet\
Services\EBCF5B90
ObjectName = "LocalSystem"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\EBCF5B90
Start = "2"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\EBCF5B90
Type = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT
ReportBootOk = "1"

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced\Folder\Hidden\
SHOWALL
CheckedValue = "0"

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
PCHealth\ErrorReporting
DoReport = "0"

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
PCHealth\ErrorReporting
ShowUI = "0"

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

It deletes the following registry keys:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\ERSvc\Parameters

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\ERSvc\Security

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\ERSvc\Enum

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\ERSvc

Dropping Routine

This worm drops the following files:

  • %System%\del.bat
  • %System%\C74F4050.DLL
  • %System Root%\auto.exe
  • d:\auto.exe
  • e:\auto.exe
  • f:\auto.exe
  • g:\auto.exe
  • h:\auto.exe
  • i:\auto.exe

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.. %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

Other Details

This worm connects to the following possibly malicious URL:

It deletes itself after execution.

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine: 9.300

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

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\SYSTEM\CurrentControlSet\Services
    • EBCF5B90

Step 3

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\SYSTEM\ControlSet001\Services\EBCF5B90
    • Description = "C74F4050"
  • In HKEY_CURRENT_USER\SYSTEM\CurrentControlSet\Services\EBCF5B90
    • Description = "C74F4050"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\EBCF5B90
    • DisplayName = "EBCF5B90"
  • In HKEY_CURRENT_USER\SYSTEM\CurrentControlSet\Services\EBCF5B90
    • DisplayName = "EBCF5B90"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\EBCF5B90
    • ErrorControl = "1"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\EBCF5B90
    • ImagePath = "%System%\9788BBD0.EXE -k"
  • In HKEY_CURRENT_USER\SYSTEM\CurrentControlSet\Services\EBCF5B90
    • ImagePath = "%System%\9788BBD0.EXE -k"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\EBCF5B90
    • ObjectName = "LocalSystem"
  • In HKEY_CURRENT_USER\SYSTEM\CurrentControlSet\Services\EBCF5B90
    • ObjectName = "LocalSystem"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\EBCF5B90
    • Start = "2"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\EBCF5B90
    • Type = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT
    • ReportBootOk = "1"

Step 4

Restore these modified registry values

[ Learn More ]

Important:Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator's help. You may also check out this Microsoft article first before modifying your computer's registry.

  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Advanced\Folder\Hidden\SHOWALL
    • From: CheckedValue = "0"
      To: CheckedValue = ""1""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\PCHealth\ErrorReporting
    • From: DoReport = "0"
      To: DoReport = ""1""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\PCHealth\ErrorReporting
    • From: ShowUI = "0"
      To: ShowUI = ""1""

Step 5

Search and delete these components

[ Learn More ]
There may be some components 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.
  • %System%\del.bat
  • %System%\C74F4050.DLL
  • %System Root%\auto.exe
  • d:\auto.exe
  • e:\auto.exe
  • f:\auto.exe
  • g:\auto.exe
  • h:\auto.exe
  • i:\auto.exe

Step 6

Scan your computer with your Trend Micro product to delete files detected as WORM_AUTORUN.IMM. 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 7

Restore this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.

  • %Windows%\SoftwareDistribution\DataStore\Logs\edbtmp.log

Step 8

Restore these deleted registry keys/values from backup

*Note: Only Microsoft-related keys/values will be restored. If the malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.

  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\ERSvc
    • Parameters
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\ERSvc
    • Security
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\ERSvc
    • Enum
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
    • ERSvc


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