Analysis by: Byron Jon Gelera
ALIASES:

Win32/InstallCore.Gen.A potentially unwanted (ESET-NOD32); PUP.Optional.InstallCore (Malwarebytes)

 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 may be manually installed by a user.

  TECHNICAL DETAILS

File Size: 1,699,837 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 29 Jan 2018

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.

It may be manually installed by a user.

Installation

This Potentially Unwanted Application adds the following folders:

  • %Program Files%\Tesi

(Note: %Program Files% is the Program Files folder, where it usually is C:\Program Files on all Windows operating system versions; C:\Program Files (x86) for 32-bit applications running on Windows 64-bit operating systems.)

It drops the following files:

  • %Program Files%\Tesi\Recodaforu.exe
  • %Program Files%\Tesi\Sedasogunoc.exe
  • %Program Files%\Tesi\unins000.dat
  • %Program Files%\Tesi\is-6VKJA.tmp
  • %Program Files%\Tesi\unins000.exe
  • %Program Files%\Tesi\is-EGO47.tmp
  • %Program Files%\Tesi\Sapipeketo.wav
  • %Program Files%\Tesi\is-KCAG3.tmp
  • %Program Files%\Tesi\Socareto.doc
  • %Program Files%\Tesi\is-UJHVK.tmp
  • %Program Files%\Tesi\Cefogim.cpp
  • %Program Files%\Tesi\is-M6PIG.tmp
  • %Program Files%\Tesi\Gidehemocata.xml
  • %Program Files%\Tesi\is-TVIB7.tmp
  • %Program Files%\Tesi\Hifemelafib.html
  • %Program Files%\Tesi\is-EOKA1.tmp
  • %Program Files%\Tesi\Lemohafal.key
  • %Program Files%\Tesi\is-HJ4KD.tmp
  • %Program Files%\Tesi\is-51UPD.tmp
  • %Program Files%\Tesi\Kihog
  • %Program Files%\Tesi\is-EOK8N.tmp
  • %Program Files%\Tesi\Todekog.msg
  • %Program Files%\Tesi\is-M754I.tmp
  • %Program Files%\Tesi\is-MOSS2.tmp
  • %Program Files%\Tesi\Merokodiginu.html
  • %Program Files%\Tesi\is-LJCEO.tmp
  • %Program Files%\Tesi\Dirake

(Note: %Program Files% is the Program Files folder, where it usually is C:\Program Files on all Windows operating system versions; C:\Program Files (x86) for 32-bit applications running on Windows 64-bit operating systems.)

Other System Modifications

This Potentially Unwanted Application adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
Tesi_is1

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
Tesi_is1
Inno Setup: Setup Version = 5.5.0 (a)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
Tesi_is1
Inno Setup: App Path = %Program Files%\Tesi

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
Tesi_is1
InstallLocation = %Program Files%\Tesi\

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
Tesi_is1
Inno Setup: Icon Group = Tesi

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
Tesi_is1
Inno Setup: User = PEWPEWPEW

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
Tesi_is1
Inno Setup: Language = default

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
Tesi_is1
DisplayName = Tesi version 1.4

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
Tesi_is1
UninstallString = "%Program Files%\Tesi\unins000.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
Tesi_is1
QuietUninstallString = "%Program Files%\Tesi\unins000.exe" /SILENT

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
Tesi_is1
DisplayVersion = 1.4

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
Tesi_is1
NoModify = 1

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
Tesi_is1
NoRepair = 1

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
Tesi_is1
InstallDate = {date}

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
Tesi_is1
MajorVersion = 1

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
Tesi_is1
MinorVersion = 4

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
Tesi_is1
EstimatedSize = 945

Other Details

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

  • http://rp.{BLOCKED}plicationscycle.com/

  SOLUTION

Minimum Scan Engine: 9.850
SSAPI PATTERN File: 1.915.00
SSAPI PATTERN Date: 01 Feb 2018

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

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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall
    • Tesi_is1

Step 4

Search and delete this folder

[ 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.
  • %Program Files%\Tesi

Step 5

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