Analysis by: Neljorn Nathaniel Aguas
ALIASES:

Virus:Win32/Sality.AT (MICROSOFT)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

Infection Channel: Downloaded from the Internet, Dropped by other malware

This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

  TECHNICAL DETAILS

File Size: 176,128 bytes
File Type: EXE
Initial Samples Received Date: 13 Sep 2024
Payload: Connects to URLs/IPs, Drops files, Modifies system registry

Arrival Details

This Trojan 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 Trojan drops the following files:

  • %User Temp%\{Random Characters}.exe
  • {Active Drive Letter}\autorun.inf
  • %Cookies%\{Username}@cupress.chula.ac[1].txt
  • {Active Drive Letter}\{Random Characters}.exe

(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).. %Cookies% is the Internet Explorer browser cookies folder, which is usually C:\Documents and Settings\{user name}\Cookies on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Roaming\Microsoft\Windows\Cookies on Windows Vista and 7, or C:\Users\{user name}\AppData\Local\Microsoft\Windows\INetCookies on Windows 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

It adds the following processes:

  • %User Temp%\{Random Characters}.exe

(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 Trojan adds the following line(s)/entry(ies) in the SYSTEM.INI file:

  • [mci]
  • [MCIDRV_VER]
  • DEVICEMB={Random Decimal Numbers}

It adds the following registry entries:

HKEY_CURRENT_USER\Software\{Derived from User Name}\
2033412880
{Derived from the first 4 letters of the User Name} = {Decimal Value}

HKEY_CURRENT_USER\Software\{Derived from User Name}\
2033412880
{Derived from the first 4 letters of the User Name} = {Hex Values}

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
AntiVirusOverride = 1

(Note: The default value data of the said registry entry is 0.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
AntiVirusDisableNotify = 1

(Note: The default value data of the said registry entry is 0.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
FirewallDisableNotify = 1

(Note: The default value data of the said registry entry is 0.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
FirewallOverride = 1

(Note: The default value data of the said registry entry is 0.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
UpdatesDisableNotify = 1

(Note: The default value data of the said registry entry is 0.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
UacDisableNotify = 1

(Note: The default value data of the said registry entry is 0.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center\Svc
AntiVirusOverride = 1

(Note: The default value data of the said registry entry is 0.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center\Svc
AntiVirusDisableNotify = 1

(Note: The default value data of the said registry entry is 0.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center\Svc
FirewallDisableNotify = 1

(Note: The default value data of the said registry entry is 0.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center\Svc
FirewallOverride = 1

(Note: The default value data of the said registry entry is 0.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center\Svc
UpdatesDisableNotify = 1

(Note: The default value data of the said registry entry is 0.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center\Svc
UacDisableNotify = 1

(Note: The default value data of the said registry entry is 0.)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings
GlobalUserOffline = 0

(Note: The default value data of the said registry entry is 1.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Policies\
System
EnableLUA = 0

(Note: The default value data of the said registry entry is 1.)

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile
EnableFirewall = 0

(Note: The default value data of the said registry entry is 1.)

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile
DoNotAllowExceptions = 0

(Note: The default value data of the said registry entry is 1.)

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile
DisableNotifications = 1

(Note: The default value data of the said registry entry is 0.)

It modifies the following registry entries to hide files with Hidden attributes:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Hidden = 2

(Note: The default value data of the said registry entry is 1.)

It deletes the following registry keys:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\Safeboot

Propagation

The said .INF file contains the following strings:

[AutoRun]
;{Garbage Characters}
SHElL\open\DefAult=1

;{Garbage Characters}
oPen={Random Characters}.exe
;{Garbage Characters}
SHell\open\commAND={Random Characters}.exe
;
ShelL\expLOre\Command = {Random Characters}.exe
;
SHell\autoPlay\comMAnd ={Random Characters}.exe

Other Details

This Trojan adds the following registry keys:

HKEY_CURRENT_USER\Software\{Derived from User Name}

HKEY_CURRENT_USER\Software\{Derived from User Name}\
2033412880

It connects to the following possibly malicious URL:

  • http://www.{BLOCKED}exi.com
  • http://www.{BLOCKED}s.chula.ac.th
  • http://{BLOCKED}ndia.com
  • http://{BLOCKED}etarlac.com
  • http://www.{BLOCKED}x-technologie.fr
  • http://www.{BLOCKED}t.my
  • {BLOCKED}.{BLOCKED}.{BLOCKED}.35

It does the following:

  • It creates a remote thread to the following process to constantly disable antivirus and showing of hidden files:
    • explorer.exe

  SOLUTION

Minimum Scan Engine: 9.800
FIRST VSAPI PATTERN FILE: 19.588.04
FIRST VSAPI PATTERN DATE: 13 Sep 2024
VSAPI OPR PATTERN File: 19.589.00
VSAPI OPR PATTERN Date: 14 Sep 2024

Step 1

Trend Micro Predictive Machine Learning detects and blocks malware at the first sign of its existence, before it executes on your system. When enabled, your Trend Micro product detects this malware under the following machine learning name:

     
    • Troj.Win32.TRX.XXPE50FFF084

Step 2

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 3

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 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_CURRENT_USER\Software\{Derived from User Name}\2033412880
    • {Derived from the first 4 letters of the User Name} = {Decimal Value}
  • In HKEY_CURRENT_USER\Software\{Derived from User Name}\2033412880
    • {Derived from the first 4 letters of the User Name} = {Hex Values}

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.

  • In HKEY_CURRENT_USER\Software\{Derived from User Name}\2033412880
  • In HKEY_CURRENT_USER\Software\{Derived from User Name}

Step 6

Restore this modified 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\Security Center
    • AntiVirusOverride = 1
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
    • AntiVirusDisableNotify = 1
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
    • FirewallDisableNotify = 1
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
    • FirewallOverride = 1
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
    • UpdatesDisableNotify = 1
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center
    • UacDisableNotify = 1
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center\Svc
    • AntiVirusOverride = 1
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center\Svc
    • AntiVirusDisableNotify = 1
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center\Svc
    • FirewallDisableNotify = 1
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center\Svc
    • FirewallOverride = 1
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center\Svc
    • UpdatesDisableNotify = 1
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center\Svc
    • UacDisableNotify = 1
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings
    • GlobalUserOffline = 0
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System
    • EnableLUA = 0
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\services\SharedAccess\Parameters\FirewallPolicy\StandardProfile
    • EnableFirewall = 0
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\services\SharedAccess\Parameters\FirewallPolicy\StandardProfile
    • DoNotAllowExceptions = 0
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\services\SharedAccess\Parameters\FirewallPolicy\StandardProfile
    • DisableNotifications = 1
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • Hidden = 2

Step 7

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.
  • %User Temp%\{Random Characters}.exe
  • {Active Drive Letter}\{Random Characters}.exe
  • %Cookies%\{Username}@cupress.chula.ac[1].txt

Step 8

Search and delete AUTORUN.INF files created by TROJ_FRS.0NA103ID24 that contain these strings

[ Learn More ]
  • In {Active Drive Letter}\autorun.inf:
    • [AutoRun]
      ;{Garbage Characters}
      SHElL\open\DefAult=1

      ;{Garbage Characters}
      oPen={Random Characters}.exe
      ;{Garbage Characters}
      SHell\open\commAND={Random Characters}.exe
      ;
      ShelL\expLOre\Command = {Random Characters}.exe
      ;
      SHell\autoPlay\comMAnd ={Random Characters}.exe

Step 9

Scan your computer with your Trend Micro product to delete files detected as TROJ_FRS.0NA103ID24. 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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