Analysis by: Clive Fuentebella

ALIASES:

Riskware/Koal (FORTINET); a variant of Win32/Koal.A (NOD32)

 PLATFORM:

Windows

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

  • Threat Type: Potentially Unwanted Application

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel: Downloaded from the Internet

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.

It does not have any information-stealing capability.

  TECHNICAL DETAILS

File Size: 759,544 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 03 Mar 2020
Payload: Connects to URLs/IPs

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:

  • %Application Data%\configtools.log → contains logs of process done
  • %Application Data%\configtools.dat → contains base64-encoded %System%\KoalCspWrapper.ocx file, and added trusted sites and certificates
  • %System%\KoalCspWrapper.ocx

(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).. %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

Autostart Technique

This Potentially Unwanted Application adds the following registry entries to enable its automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{Generated ID-4}\InprocServer32
(Default) = %System%\KOALCS~1.OCX

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{Generated ID-5}\InprocServer32
(Default) = %System%\KOALCS~1.OCX

Other System Modifications

This Potentially Unwanted Application adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
TypeLib\{Generated ID-1}\1.0
(Default) = KoalCspWrapper ActiveX Control module

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
TypeLib\{Generated ID-1}\1.0\
FLAGS
(Default) = 2

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
TypeLib\{Generated ID-1}\1.0\
0\win32
(Default) = %System%\KoalCspWrapper.ocx

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{Generated ID-2}
(Default) = _DKoalCspWrapper

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{Generated ID-2}\ProxyStubClsid
(Default) = {Proxy Stub ID}

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{Generated ID-2}\ProxyStubClsid32
(Default) = {Proxy Stub ID}

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{Generated ID-2}\TypeLib
(Default) = {Generated ID-1}

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{Generated ID-2}\TypeLib
Version = 1.0

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{Generated ID-3}
(Default) = _DKoalCspWrapperEvents

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{Generated ID-3}\ProxyStubClsid
(Default) = {Proxy Stub ID}

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{Generated ID-3}\ProxyStubClsid32
(Default) = {Proxy Stub ID}

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{Generated ID-3}\TypeLib
(Default) = {Generated ID-1}

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{Generated ID-3}\TypeLib
Version = 1.0

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{Generated ID-4}
(Default) = KoalCspWrapper Property Page

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{Generated ID-4}\InprocServer32
(Default) = %System%\KOALCS~1.OCX

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
KoalEAClient.CspWrapper.1
(Default) = KoalCspWrapper Control

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
KoalEAClient.CspWrapper.1\CLSID
(Default) = {Generated ID-5}

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{Generated ID-5}
(Default) = KoalCspWrapper Control

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{Generated ID-5}\ProgID
(Default) = KoalEAClient.CspWrapper.1

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{Generated ID-5}\ToolboxBitmap32
(Default) = %System%\KOALCS~1.OCX, 1

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{Generated ID-5}\MiscStatus
(Default) = 0

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{Generated ID-5}\MiscStatus\
1
(Default) = 131473

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{Generated ID-5}\TypeLib
(Default) = {Generated ID-1}

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{Generated ID-5}\Version
(Default) = 1.0

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{Generated ID-5}\InprocServer32
ThreadingModel = Apartment

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Component Categories\{ID}
409 = Controls safely initializable from persistent data!

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Component Categories\{ID}
409 = Controls safely scriptable!

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
SystemCertificates\ROOT\Certificates\
b26fa75369d6fd879204d8e67fcc105ef35fcd84
Blob = {Blob data}

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
SystemCertificates\CA\Certificates\
d2ea461e09eeb661f39dd88f63b2d1b592a7d341
Blob = {Blob data}

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.

Information Theft

This Potentially Unwanted Application does not have any information-stealing capability.

Other Details

This Potentially Unwanted Application adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
TypeLib\{Generated ID-1}

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
TypeLib\{Generated ID-1}\1.0

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
TypeLib\{Generated ID-1}\1.0\
FLAGS

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
TypeLib\{Generated ID-1}\1.0\
0

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
TypeLib\{Generated ID-1}\1.0\
0\win32

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
TypeLib\{Generated ID-1}\1.0\
HELPDIR

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{Generated ID-2}

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{Generated ID-2}\ProxyStubClsid

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{Generated ID-2}\ProxyStubClsid32

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
Interface\{Generated ID-2}\TypeLib

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{Generated ID-4}

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{Generated ID-4}\InprocServer32

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{Generated ID-5}

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
KoalEAClient.CspWrapper.1

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
KoalEAClient.CspWrapper.1\CLSID

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{Generated ID-5}\ProgID

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{Generated ID-5}\InprocServer32

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{Generated ID-5}\ToolboxBitmap32

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{Generated ID-5}\MiscStatus

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{Generated ID-5}\MiscStatus\
1

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{Generated ID-5}\Control

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{Generated ID-5}\TypeLib

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{Generated ID-5}\Version

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{Generated ID-5}\Implemented Categories

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{Generated ID-5}\Implemented Categories\
{ID}

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{Generated ID-6}

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{Generated ID-6}\Implemented Categories

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{Generated ID-6}\Implemented Categories\
{ID}

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
SystemCertificates\ROOT\Certificates\
b26fa75369d6fd879204d8e67fcc105ef35fcd84

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
SystemCertificates\CA\Certificates\
d2ea461e09eeb661f39dd88f63b2d1b592a7d341

It displays the following images:

It does the following:

  • It adds the following sites to the system's trusted sites:
    • http://{BLOCKED}.{BLOCKED}.156.9
    • http://{Any subdomain}.{BLOCKED}.gov.cn
    • https://ytb.{BLOCKED}.gov.cn
  • It installs the following certificates in the system:
    • [Trusted Root Certification Authorities]
      Issued by: NBSROOT
      Issued to: NBSROOT
      Thumbprint: b26fa75369d6fd879204d8e67fcc105ef35fcd84
    • [Intermediate Certification Authorities]
      Issued by: NBSROOT
      Issued to: AHCA
      Thumbprint: d2ea461e09eeb661f39dd88f63b2d1b592a7d341

It does not exploit any vulnerability.

  SOLUTION

Minimum Scan Engine: 9.850
SSAPI PATTERN File: 2.268.00
SSAPI PATTERN Date: 12 Mar 2020

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

Restart in Safe Mode

[ Learn More ]

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_LOCAL_MACHINE\SOFTWARE\Classes\TypeLib\{Generated ID-1}\1.0
    • (Default) = KoalCspWrapper ActiveX Control module
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\TypeLib\{Generated ID-1}\1.0\FLAGS
    • (Default) = 2
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\TypeLib\{Generated ID-1}\1.0\0\win32
    • (Default) = %System%\KoalCspWrapper.ocx
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{Generated ID-2}
    • (Default) = _DKoalCspWrapper
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{Generated ID-2}\ProxyStubClsid
    • (Default) = {Proxy Stub ID}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{Generated ID-2}\ProxyStubClsid32
    • (Default) = {Proxy Stub ID}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{Generated ID-2}\TypeLib
    • (Default) = {Generated ID-1}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{Generated ID-2}\TypeLib
    • Version = 1.0
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{Generated ID-3}
    • (Default) = _DKoalCspWrapperEvents
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{Generated ID-3}\ProxyStubClsid
    • (Default) = {Proxy Stub ID}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{Generated ID-3}\ProxyStubClsid32
    • (Default) = {Proxy Stub ID}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{Generated ID-3}\TypeLib
    • (Default) = {Generated ID-1}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{Generated ID-3}\TypeLib
    • Version = 1.0
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{Generated ID-4}
    • (Default) = KoalCspWrapper Property Page
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{Generated ID-4}\InprocServer32
    • (Default) = %System%\KOALCS~1.OCX
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\KoalEAClient.CspWrapper.1
    • (Default) = KoalCspWrapper Control
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\KoalEAClient.CspWrapper.1\CLSID
    • (Default) = {Generated ID-5}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{Generated ID-5}
    • (Default) = KoalCspWrapper Control
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{Generated ID-5}\ProgID
    • (Default) = KoalEAClient.CspWrapper.1
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{Generated ID-5}\ToolboxBitmap32
    • (Default) = %System%\KOALCS~1.OCX, 1
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{Generated ID-5}\MiscStatus
    • (Default) = 0
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{Generated ID-5}\MiscStatus\1
    • (Default) = 131473
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{Generated ID-5}\TypeLib
    • (Default) = {Generated ID-1}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{Generated ID-5}\Version
    • (Default) = 1.0
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{Generated ID-5}\InprocServer32
    • ThreadingModel = Apartment
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Component Categories\{ID}
    • 409 = Controls safely initializable from persistent data!
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Component Categories\{ID}
    • 409 = Controls safely scriptable!
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\SystemCertificates\ROOT\Certificates\b26fa75369d6fd879204d8e67fcc105ef35fcd84
    • Blob = {Blob data}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\SystemCertificates\CA\Certificates\d2ea461e09eeb661f39dd88f63b2d1b592a7d341
    • Blob = {Blob data}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{Generated ID-4}\InprocServer32
    • (Default) = %System%\KOALCS~1.OCX
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{Generated ID-5}\InprocServer32
    • (Default) = %System%\KOALCS~1.OCX

Step 5

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. Before you could do this, you must restart in Safe Mode. For instructions on how to do this, you may refer to this page If the preceding step requires you to restart in safe mode, you may proceed to edit the system registry.

 
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\TypeLib
    • {Generated ID-1}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface
    • {Generated ID-2}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID
    • {Generated ID-4}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID
    • {Generated ID-5}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes
    • KoalEAClient.CspWrapper.1
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID
    • {Generated ID-6}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\SystemCertificates\ROOT\Certificates
    • b26fa75369d6fd879204d8e67fcc105ef35fcd84
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\SystemCertificates\CA\Certificates
    • d2ea461e09eeb661f39dd88f63b2d1b592a7d341

Step 6

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.
  • %Application Data%\configtools.log
  • %Application Data%\configtools.dat
  • %System%\KoalCspWrapper.ocx

Step 7

Restart in normal mode and scan your computer with your Trend Micro product for files detected as PUA.Win32.Koal.AZ. 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 this Knowledge Base page for more information.


Did this description help? Tell us how we did.