PUA_Offercast

April 17, 2023
 Analysis by: Rhena Inocencio
 Modified by: Jayvee Mark Villaroman
 ALIASES:

UDS:WebToolbar.Win32.Asparnet.gen (KASPERSKY)

 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 creates folders where it drops its files.

  TECHNICAL DETAILS

File Size:

2,570,096 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

20 Oct 2022

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 adds the following processes:

  • %User Temp%\{random strings}.tmp\{Malware Name}.tmp" /SL5="$210440,2294051,56832,{Malware Directory}\{Malware Name}.exe"
  • %User Temp%\{random strings}.tmp\Offercast391_ARS_.exe
  • %Program Files%\Internet Explorer\iexplore.exe" -nohome

(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).. %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).)

It creates the following folders:

  • %User Temp%\{random strings}.tmp

(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 Details

This Potentially Unwanted Application adds the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft
RestartManager = Session0000

HKEY_LOCAL_MACHINE
SOFTWARE = APN PIP

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft
Tracing = Offercast391_ARS__RASAPI32

It connects to the following possibly malicious URL:

  • http://ak.pipoffers.{BLOCKED}tners.com
  • http://pipoffers.{BOCKED}tners.com
  • http://www.{BLOCKED}f-editor.com

  SOLUTION

Minimum Scan Engine:

9.800

SSAPI PATTERN File:

1.717.00

SSAPI PATTERN Date:

24 Mar 2016

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 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\Microsoft\RestartManager\Session0000
  • In HKEY_LOCAL_MACHINE\SOFTWARE\APN PIP
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Tracing\Offercast391_ARS__RASAPI32

Step 4

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%\{random strings}.tmp

Step 5

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