PUA.Win32.Installcore.MANHOCFF

December 06, 2023
 Analysis by: John Rainier Navato
 ALIASES:

Win32/InstallCore.Gen.A (NOD32)

 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

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.

It does not have any propagation routine.

It does not have any backdoor routine.

However, as of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size:

808,768 bytes

File Type:

, EXE

Memory Resident:

No

Initial Samples Received Date:

22 Nov 2023

Payload:

Connects to URLs/IPs, Deletes files, Creates files, Modifies system registry

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:

  • %Desktop%\Continue Download Manager Installation.lnk
  • %Program Files%\is{Random}.log
  • %User Temp%\ICReinstall_{Malware File Name}
  • %User Temp%\ish{Random}\bootstrap_32821.html
  • %User Temp%\ish{Random}\css\ie6_main.css
  • %User Temp%\ish{Random}\css\main.css
  • %User Temp%\ish{Random}\css\sdk-ui\browse.css
  • %User Temp%\ish{Random}\css\sdk-ui\button.css
  • %User Temp%\ish{Random}\css\sdk-ui\checkbox.css
  • %User Temp%\ish{Random}\css\sdk-ui\images\button-bg.png
  • %User Temp%\ish{Random}\css\sdk-ui\images\progress-bg-corner.png
  • %User Temp%\ish{Random}\css\sdk-ui\images\progress-bg.png
  • %User Temp%\ish{Random}\css\sdk-ui\images\progress-bg2.png
  • %User Temp%\ish{Random}\css\sdk-ui\progress-bar.css
  • %User Temp%\ish{Random}\csshover3.htc
  • %User Temp%\ish{Random}\dat\upd.DAT
  • %User Temp%\ish{Random}\form.bmp.Mask
  • %User Temp%\ish{Random}\images\BG.png
  • %User Temp%\ish{Random}\images\Close.png
  • %User Temp%\ish{Random}\images\Close_Hover.png
  • %User Temp%\ish{Random}\images\Color_Button.png
  • %User Temp%\ish{Random}\images\Color_Button_Hover.png
  • %User Temp%\ish{Random}\images\Grey_Button.png
  • %User Temp%\ish{Random}\images\Grey_Button_Hover.png
  • %User Temp%\ish{Random}\images\Loader.gif
  • %User Temp%\ish{Random}\images\Logo.png
  • %User Temp%\ish{Random}\images\Progress.png
  • %User Temp%\ish{Random}\images\ProgressBar.png
  • %User Temp%\ish{Random}\images\text-bg.png
  • %User Temp%\ish{Random}\locale\DE.locale
  • %User Temp%\ish{Random}\locale\EN.locale
  • %User Temp%\ish{Random}\locale\ES.locale
  • %User Temp%\ish{Random}\locale\FR.locale
  • %User Temp%\ish{Random}\locale\IT.locale
  • %User Temp%\ish{Random}\locale\PL.locale
  • %User Temp%\ish{Random}\locale\PT.locale
  • %User Temp%\ish{Random}\locale\RU.locale
  • %User Temp%\ish{Random}\locale\UA.locale
  • %User Temp%\is{Random}\{Random}_stp.EXE
  • %User Temp%\is{Random}\{Random}_stp.EXE.part
  • %User Temp%\{Random}.log

(Note: %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).. %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000(32-bit), Server 2003(32-bit), XP, Vista(64-bit), 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit) , or C:\Program Files (x86) in Windows XP(64-bit), Vista(64-bit), 7(64-bit), 8(64-bit), 8.1(64-bit), 2008(64-bit), 2012(64-bit) and 10(64-bit).. %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

It creates the following folders:

  • %User Temp%\ish{Random}
  • %User Temp%\ish{Random}\css
  • %User Temp%\ish{Random}\css\sdk-ui
  • %User Temp%\ish{Random}\css\sdk-ui\images
  • %User Temp%\ish{Random}\dat
  • %User Temp%\ish{Random}\images
  • %User Temp%\ish{Random}\locale

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

Other System Modifications

This Potentially Unwanted Application deletes the following files:

  • %Desktop%\Continue Download Manager Installation.lnk
  • %Program Files%\is{Random}.log
  • %User Temp%\ICReinstall_{Malware File Name}
  • %User Temp%\ish{Random}\bootstrap_{Random}.html
  • %User Temp%\ish{Random}\css\ie6_main.css
  • %User Temp%\ish{Random}\css\main.css
  • %User Temp%\ish{Random}\css\sdk-ui\browse.css
  • %User Temp%\ish{Random}\css\sdk-ui\button.css
  • %User Temp%\ish{Random}\css\sdk-ui\checkbox.css
  • %User Temp%\ish{Random}\css\sdk-ui\images\button-bg.png
  • %User Temp%\ish{Random}\css\sdk-ui\images\progress-bg-corner.png
  • %User Temp%\ish{Random}\css\sdk-ui\images\progress-bg.png
  • %User Temp%\ish{Random}\css\sdk-ui\images\progress-bg2.png
  • %User Temp%\ish{Random}\css\sdk-ui\progress-bar.css
  • %User Temp%\ish{Random}\csshover3.htc
  • %User Temp%\ish{Random}\dat\upd.DAT
  • %User Temp%\ish{Random}\form.bmp.Mask
  • %User Temp%\ish{Random}\images\BG.png
  • %User Temp%\ish{Random}\images\Close.png
  • %User Temp%\ish{Random}\images\Close_Hover.png
  • %User Temp%\ish{Random}\images\Color_Button.png
  • %User Temp%\ish{Random}\images\Color_Button_Hover.png
  • %User Temp%\ish{Random}\images\Grey_Button.png
  • %User Temp%\ish{Random}\images\Grey_Button_Hover.png
  • %User Temp%\ish{Random}\images\Loader.gif
  • %User Temp%\ish{Random}\images\Logo.png
  • %User Temp%\ish{Random}\images\Progress.png
  • %User Temp%\ish{Random}\images\ProgressBar.png
  • %User Temp%\ish{Random}\images\text-bg.png
  • %User Temp%\ish{Random}\locale\DE.locale
  • %User Temp%\ish{Random}\locale\EN.locale
  • %User Temp%\ish{Random}\locale\ES.locale
  • %User Temp%\ish{Random}\locale\FR.locale
  • %User Temp%\ish{Random}\locale\IT.locale
  • %User Temp%\ish{Random}\locale\PL.locale
  • %User Temp%\ish{Random}\locale\PT.locale
  • %User Temp%\ish{Random}\locale\RU.locale
  • %User Temp%\ish{Random}\locale\UA.locale
  • %User Temp%\{Random}.log

(Note: %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).. %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000(32-bit), Server 2003(32-bit), XP, Vista(64-bit), 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit) , or C:\Program Files (x86) in Windows XP(64-bit), Vista(64-bit), 7(64-bit), 8(64-bit), 8.1(64-bit), 2008(64-bit), 2012(64-bit) and 10(64-bit).. %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

It deletes the following folders:

  • %User Temp%\ish{Random}\css\sdk-ui\images
  • %User Temp%\ish{Random}\css\sdk-ui
  • %User Temp%\ish{Random}\css
  • %User Temp%\ish{Random}\dat
  • %User Temp%\ish{Random}\images
  • %User Temp%\ish{Random}\locale
  • %User Temp%\ish{Random}

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

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Tracing\DownloadManagerSetup_RASAPI32
EnableFileTracing = 0

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Tracing\DownloadManagerSetup_RASAPI32
EnableConsoleTracing = 0

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Tracing\DownloadManagerSetup_RASAPI32
FileTracingMask = {Random}

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Tracing\DownloadManagerSetup_RASAPI32
ConsoleTracingMask = {Random}

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Tracing\DownloadManagerSetup_RASAPI32
MaxFileSize = 1048576

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Tracing\DownloadManagerSetup_RASAPI32
FileDirectory = %windir%\tracing

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Tracing\DownloadManagerSetup_RASMANCS
EnableFileTracing = 0

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Tracing\DownloadManagerSetup_RASMANCS
EnableConsoleTracing = 0

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Tracing\DownloadManagerSetup_RASMANCS
FileTracingMask = {Random}

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Tracing\DownloadManagerSetup_RASMANCS
ConsoleTracingMask = {Random}

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Tracing\DownloadManagerSetup_RASMANCS
MaxFileSize = 1048576

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Tracing\DownloadManagerSetup_RASMANCS
FileDirectory = %windir%\tracing

HKEY_CURRENT_USER\Software\Microsoft\
Windows Script\Settings
JITDebug = 0

It adds the following registry keys as part of its installation routine:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Tracing\DownloadManagerSetup_RASAPI32

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Tracing\DownloadManagerSetup_RASMANCS

Propagation

This Potentially Unwanted Application does not have any propagation routine.

Backdoor Routine

This Potentially Unwanted Application does not have any backdoor routine.

Rootkit Capabilities

This Potentially Unwanted Application does not have rootkit capabilities.

Download Routine

This Potentially Unwanted Application connects to the following URL(s) to download its component file(s):

  • http://{BLOCKED}d.com/widget/render/hash/{Random}
  • http://{BLOCKED}download-manager.com/CM_DS/?v=3.0&c={Random}
  • http://{BLOCKED}download-manager.com/Aff-AD/?v=3.0&c={Random}
  • http://{BLOCKED}download-manager.com/?pcrc={Random}
  • http://{BLOCKED}onaws.com/Adlsoft/releases/DownloadManagerV2.exe

Other Details

This Potentially Unwanted Application does the following:

  • It displays the following GUI to install Download Manager:


  • It redirects browsers to the following site:
    • http://www.{BLOCKED}tdownload-manager.com/download-manager/welcome/oc/?&adnm={Random}&i=s&grid=&lg=ja&cc=JP&clg=ja&c=1&d=0&cid=_{Random}&kw=microsoftダウンロードマネージャー&mt=&mn=www.{BLOCKED}ol.com&ct=&nt=D&expr=&ap=none&dv=c&agid=_{Random}&gclid={Random}&iv=0

However, as of this writing, the said sites are inaccessible.

It does not exploit any vulnerability.

  SOLUTION

Minimum Scan Engine:

9.800

SSAPI PATTERN File:

2.681.00

SSAPI PATTERN Date:

07 Dec 2023

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

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\Tracing\DownloadManagerSetup_RASAPI32
    • EnableFileTracing = 0
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Tracing\DownloadManagerSetup_RASAPI32
    • EnableConsoleTracing = 0
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Tracing\DownloadManagerSetup_RASAPI32
    • FileTracingMask = {Random}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Tracing\DownloadManagerSetup_RASAPI32
    • ConsoleTracingMask = {Random}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Tracing\DownloadManagerSetup_RASAPI32
    • MaxFileSize data = 1048576
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Tracing\DownloadManagerSetup_RASAPI32
    • FileDirectory = %windir%\tracing
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Tracing\DownloadManagerSetup_RASMANCS
    • EnableFileTracing = 0
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Tracing\DownloadManagerSetup_RASMANCS
    • EnableConsoleTracing = 0
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Tracing\DownloadManagerSetup_RASMANCS
    • FileTracingMask = {Random}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Tracing\DownloadManagerSetup_RASMANCS
    • ConsoleTracingMask = {Random}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Tracing\DownloadManagerSetup_RASMANCS
    • MaxFileSize = 1048576
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Tracing\DownloadManagerSetup_RASMANCS
    • FileDirectory = %windir%\tracing
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows Script\Settings
    • JITDebug = 0

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_LOCAL_MACHINE\SOFTWARE\Microsoft\Tracing
    • DownloadManagerSetup_RASAPI32
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Tracing
    • DownloadManagerSetup_RASMANCS

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.  
  • %Desktop%\Continue Download Manager Installation.lnk
  • %Program Files%\is{Random}.log
  • %User Temp%ICReinstall_{Malware File Name}
  • %User Temp%ish{Random}\bootstrap_32821.html
  • %User Temp%ish{Random}\css\ie6_main.css
  • %User Temp%ish{Random}\css\main.css
  • %User Temp%ish{Random}\css\sdk-ui\browse.css
  • %User Temp%ish{Random}\css\sdk-ui\button.css
  • %User Temp%ish{Random}\css\sdk-ui\checkbox.css
  • %User Temp%ish{Random}\css\sdk-ui\images\button-bg.png
  • %User Temp%ish{Random}\css\sdk-ui\images\progress-bg-corner.png
  • %User Temp%ish{Random}\css\sdk-ui\images\progress-bg.png
  • %User Temp%ish{Random}\css\sdk-ui\images\progress-bg2.png
  • %User Temp%ish{Random}\css\sdk-ui\progress-bar.css
  • %User Temp%ish{Random}\csshover3.htc
  • %User Temp%ish{Random}\dat\upd.DAT
  • %User Temp%ish{Random}\form.bmp.Mask
  • %User Temp%ish{Random}\images\BG.png
  • %User Temp%ish{Random}\images\Close.png
  • %User Temp%ish{Random}\images\Close_Hover.png
  • %User Temp%ish{Random}\images\Color_Button.png
  • %User Temp%ish{Random}\images\Color_Button_Hover.png
  • %User Temp%ish{Random}\images\Grey_Button.png
  • %User Temp%ish{Random}\images\Grey_Button_Hover.png
  • %User Temp%ish{Random}\images\Loader.gif
  • %User Temp%ish{Random}\images\Logo.png
  • %User Temp%ish{Random}\images\Progress.png
  • %User Temp%ish{Random}\images\ProgressBar.png
  • %User Temp%ish{Random}\images\text-bg.png
  • %User Temp%ish{Random}\locale\DE.locale
  • %User Temp%ish{Random}\locale\EN.locale
  • %User Temp%ish{Random}\locale\ES.locale
  • %User Temp%ish{Random}\locale\FR.locale
  • %User Temp%ish{Random}\locale\IT.locale
  • %User Temp%ish{Random}\locale\PL.locale
  • %User Temp%ish{Random}\locale\PT.locale
  • %User Temp%ish{Random}\locale\RU.locale
  • %User Temp%ish{Random}\locale\UA.locale
  • %User Temp%is{Random}\{Random}_stp.EXE
  • %User Temp%is{Random}\{Random}_stp.EXE.part
  • %User Temp%{Random}.log

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.
  • %User Temp%\ish{Random}\css\sdk-ui\images
  • %User Temp%\ish{Random}\css\sdk-ui
  • %User Temp%\ish{Random}\css
  • %User Temp%\ish{Random}\dat
  • %User Temp%\ish{Random}\images
  • %User Temp%\ish{Random}\locale
  • %User Temp%\ish{Random}

Step 7

Scan your computer with your Trend Micro product to delete files detected as PUA.Win32.Installcore.MANHOCFF. 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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