Author: Neljorn Nathaniel Aguas   
 

PUA/OfferCore.Gen (ANTIVIR)

 PLATFORM:

Windows

 OVER ALL RISK RATING:
 DAMAGE POTENTIAL::
 DISTRIBUTION POTENTIAL::
 REPORTED INFECTION:
 INFORMATION EXPOSURE:
Low
Medium
High
Critical

  • Threat Type:
    Potentially Unwanted Application

  • Destructiveness:
    No

  • Encrypted:
     

  • In the wild::
    Yes


  TECHNICAL DETAILS

File size: 1,734,816 bytes
File type: EXE
Memory resident: No
INITIAL SAMPLES RECEIVED DATE: 31 sierpnia 2023
PAYLOAD: Connects to URLs/IPs, Drops files

Instalación

Infiltra los archivos siguientes:

  • %User Temp%\is-{Random Characters 1}.tmp\{Malware File Name}.tmp → Deleted afterwards
  • %User Temp%\is-{Random Characters 2}.tmp\is-{Random Characters 3}.tmp → Renamed afterwards to file_.exe
  • %User Temp%\is-{Random Characters 4}.tmp\file_.tmp → Deleted afterwards
  • %User Temp%\is-{Random Characters 5}.tmp\botva2.dll → Deleted afterwards
  • %User Temp%\is-{Random Characters 5}.tmp\Helper.dll → Deleted afterwards

(Nota: %User Temp% es la carpeta Temp del usuario activo, que en el caso de Windows 2000(32-bit), XP y Server 2003(32-bit) suele estar en C:\Documents and Settings\{nombre de usuario}\Local Settings\Temp y en el case de Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) y 10(64-bit) en C:\Users\{nombre de usuario}\AppData\Local\Temp).

)

Agrega los procesos siguientes:

  • "%User Temp%\is-{Random Characters 1}.tmp\{Malware File Name}.tmp" /SL5="$1F05E8,831488,831488,{Malware Path}\{Malware File Name}.exe"
  • "%User Temp%\is-{Random Characters 2}.tmp\file_.exe" /LANG=en /NA=Rh85hR64
  • "%User Temp%\is-{Random Characters 4}.tmp\file_.tmp" /SL5="$2F05AA,1559708,780800,%User Temp%\is-{Random Characters 2}.tmp\file_.exe" /LANG=en /NA=Rh85hR64

(Nota: %User Temp% es la carpeta Temp del usuario activo, que en el caso de Windows 2000(32-bit), XP y Server 2003(32-bit) suele estar en C:\Documents and Settings\{nombre de usuario}\Local Settings\Temp y en el case de Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) y 10(64-bit) en C:\Users\{nombre de usuario}\AppData\Local\Temp).

)

Crea las carpetas siguientes:

  • %User Temp%\is-{Random Characters 1}.tmp → Deleted afterwards
  • %User Temp%\is-{Random Characters 2}.tmp
  • %User Temp%\is-{Random Characters 2}.tmp\_isetup
  • %User Temp%\is-{Random Characters 4}.tmp → Deleted afterwards
  • %User Temp%\is-{Random Characters 5}.tmp → Deleted afterwards
  • %User Temp%\is-{Random Characters 5}.tmp\_isetup → Deleted afterwards

(Nota: %User Temp% es la carpeta Temp del usuario activo, que en el caso de Windows 2000(32-bit), XP y Server 2003(32-bit) suele estar en C:\Documents and Settings\{nombre de usuario}\Local Settings\Temp y en el case de Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) y 10(64-bit) en C:\Users\{nombre de usuario}\AppData\Local\Temp).

)

Otras modificaciones del sistema

Agrega las siguientes entradas de registro:

HKEY_CURRENT_USER\Software\Microsoft\
RestartManager\Session0000
Owner = {Hex Values}

HKEY_CURRENT_USER\Software\Microsoft\
RestartManager\Session0000
SessionHash = {Hex Values}

HKEY_CURRENT_USER\Software\Microsoft\
RestartManager\Session0000
Sequence = 1

HKEY_CURRENT_USER\Software\Microsoft\
RestartManager\Session0001
Owner = {Hex Values} → Deleted afterwards

HKEY_CURRENT_USER\Software\Microsoft\
RestartManager\Session0001
SessionHash = {Hex Values} → Deleted afterwards

HKEY_CURRENT_USER\Software\Microsoft\
RestartManager\Session0001
Sequence = 1 → Deleted afterwards

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
SystemCertificates\AuthRoot\Certificates\
{Hash Value}
Blob = {Hex Values}

Otros detalles

It connects to the following possibly malicious URL:

  • http://{BLOCKED}9k18f2wb.cloudfront.net
  • http://{BLOCKED}ha0gj0a4.cloudfront.net