Analysis by: Raymart Christian Yambot
ALIASES:

Win64:PUP-gen [PUP] (AVAST)

 PLATFORM:

Windows

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

  • Threat Type: Potentially Unwanted Application

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

Infection Channel: Downloaded from the Internet, Dropped by other malware

This Potentially Unwanted Application arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

  TECHNICAL DETAILS

File Size: 8,507,584 bytes
File Type: EXE
Initial Samples Received Date: 15 Apr 2024
Payload: Connects to URLs/IPs, Creates files, Drops files

Arrival Details

This Potentially Unwanted Application 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 Potentially Unwanted Application drops the following files:

  • %Cookies%\{Random Characters}.txt
  • %Cookies%\{Random Characters}.txt
  • %Temporary Internet Files%\Content.IE5\{Random Characters}\{Random Characters}.htm
  • %Temporary Internet Files%\Content.IE5\{Random Characters}\css2[1].css
  • %Temporary Internet Files%\Content.IE5\{Random Characters}\email-decode.min[1].js
  • %Temporary Internet Files%\Content.IE5\{Random Characters}\font[1].eot
  • %Application Data%\SumatraPDF\SumatraPDF-3.5.2-64.exe
  • %Application Data%\SumatraPDF\SumatraPDF-settings.txt
  • %Application Data%\SumatraPDF\SumatraPDF.zip → Deleted Aftewards
  • %Desktop%\SumatraPDF-3.5.2-64.lnk

(Note: %Cookies% is the Internet Explorer browser cookies folder, which is usually C:\Documents and Settings\{user name}\Cookies on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Roaming\Microsoft\Windows\Cookies on Windows Vista and 7, or C:\Users\{user name}\AppData\Local\Microsoft\Windows\INetCookies on Windows 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).. %Temporary Internet Files% is the Temporary Internet Files folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temporary Internet Files on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local\Microsoft\Windows\Temporary Internet Files on Windows Vista, 7 and 2008(64-bit), or C:\Users\{user name}\AppData\Local\Microsoft\Windows\INetCache on Windows 8, 8.1, 2012(64-bit) and 10(64-bit).. %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).. %Desktop% is the current user's desktop, which is usually C:\Documents and Settings\{User Name}\Desktop on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\Desktop on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

It adds the following processes:

  • %Application Data%\SumatraPDF\SumatraPDF-3.5.2-64.exe

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

It creates the following folders:

  • %Temporary Internet Files%\Content.IE5\{Random Characters}
  • %Temporary Internet Files%\Content.IE5\{Random Characters}
  • %Temporary Internet Files%\Content.IE5\{Random Characters}
  • %Application Data%\SumatraPDF

(Note: %Temporary Internet Files% is the Temporary Internet Files folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temporary Internet Files on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local\Microsoft\Windows\Temporary Internet Files on Windows Vista, 7 and 2008(64-bit), or C:\Users\{user name}\AppData\Local\Microsoft\Windows\INetCache on Windows 8, 8.1, 2012(64-bit) and 10(64-bit).. %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

Other System Modifications

This Potentially Unwanted Application adds the following registry entries:

HKEY_CURRENT_USER\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
SumatraPDFUninstall]
UninstallString = cmd /c rmdir /s /q "%Application Data%\SumatraPDF" & del "%Desktop%\SumatraPDF.lnk" & reg delete HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Uninstall\SumatraPDFUninstall /f

It modifies the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
ZoneMap
UNCAsIntranet = 0

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
ZoneMap
AutoDetect = 1

(Note: The default value data of the said registry entry is 0.)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings
ProxyEnable = 0

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Wpad\{GUID}
WpadDecision = 0

(Note: The default value data of the said registry entry is 3.)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Wpad\{GUID}
WpadNetworkName = Network 7

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

Other Details

This Potentially Unwanted Application connects to the following possibly malicious URL:

  • https://{BLOCKED}dfixers.com

  SOLUTION

Minimum Scan Engine: 9.800
SSAPI PATTERN File: 2.721.00
SSAPI PATTERN Date: 18 Apr 2024

Step 1

Before doing any scans, Windows 7, Windows 8, Windows 8.1, and Windows 10 users must disable System Restore to allow full scanning of their computers.

Step 2

Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

Step 3

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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\ZoneMap
    • UNCAsIntranet = 0
    • UNCAsIntranet = 1 (Original value)
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\ZoneMap
    • AutoDetect = 1
    • AutoDetect = 0 (Original value)
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings
    • ProxyEnable = 0
    • ProxyEnable = 1 (Original value)
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Wpad\{GUID}
    • WpadDecision = 0
    • WpadDecision = 3 (Original value)
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Wpad\{GUID}
    • WpadNetworkName = Network 7
    • WpadNetworkName = Network (Original value)

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\Uninstall\SumatraPDFUninstall
  • In UninstallString = cmd /c rmdir /s /q "%Application Data%\SumatraPDF" & del "%Desktop%\SumatraPDF.lnk" & reg delete HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Uninstall\SumatraPDFUninstall /f

Step 5

Search and delete these files

[ Learn More ]
There may be some files 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.
  • %Cookies%\{Random Characters}.txt
  • %Cookies%\{Random Characters}.txt
  • %Temporary Internet Files%\Content.IE5\{Random Characters}\{Random Characters}.htm
  • %Temporary Internet Files%\Content.IE5\{Random Characters}\css2[1].css
  • %Temporary Internet Files%\Content.IE5\{Random Characters}\email-decode.min[1].js
  • %Temporary Internet Files%\Content.IE5\{Random Characters}\font[1].eot
  • %Application Data%\SumatraPDF\SumatraPDF-3.5.2-64.exe
  • %Application Data%\SumatraPDF\SumatraPDF-settings.txt
  • %Application Data%\SumatraPDF\SumatraPDF.zip
  • %Desktop%\SumatraPDF-3.5.2-64.lnk

Step 6

Search and delete these folders

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • %Temporary Internet Files%\Content.IE5\{Random Characters}
  • %Temporary Internet Files%\Content.IE5\{Random Characters}
  • %Temporary Internet Files%\Content.IE5\{Random Characters}
  • %Application Data%\SumatraPDF

Step 7

Scan your computer with your Trend Micro product to delete files detected as PUA.MSIL.PDFFixers.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 the following Trend Micro Support pages for more information:


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