Analysis by: Thea Patrice Tajonera
ALIASES:

INF/Agent.J trojan (NOD32)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Canal de infección Downloaded from the Internet

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.

It automatically executes files when a user opens a drive.

  TECHNICAL DETAILS

Tamaño del archivo 583 bytes
Tipo de archivo INF
Residente en memoria No
Fecha de recepción de las muestras iniciales 07 Jan 2021
Carga útil Executes files

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.

Propagation

The said .INF file contains the following strings:

[version]
Signature=$chicago$
AdvancedINF=2.5

[DefaultInstall]
CustomDestination=CustInstDestSectionAllUsers

RunPreSetupCommands=RunPreSetupCommandsSection

[RunPreSetupCommandsSection]
; Commands Here will be run Before Setup Begins to install
cmd /c start "C:\Windows\temp\{Random Characters}.exe"
taskkill /IM cmstp.exe /F

[CustInstDestSectionAllUsers]
49000,49001=AllUSer_LDIDSection, 7

[AllUSer_LDIDSection]
"HKLM", "SOFTWARE\Microsoft\Windows\CurrentVersion\App Paths\CMMGR32.EXE", "ProfileInstallPath", "%UnexpectedError%", ""

[Strings]
ServiceName="Crimson"
ShortSvcName="Crimson"

Other Details

This Trojan automatically executes the following files when a user opens a drive:

  • C:\Windows\temp\{Random Characters}.exe
  • taskkill /IM cmstp.exe /F

  SOLUTION

Motor de exploración mínimo 9.800
Primer archivo de patrones de VSAPI 16.462.06
Primera fecha de publicación de patrones de VSAPI 07 Jan 2021
Versión de patrones OPR de VSAPI 16.463.00
Fecha de publicación de patrones OPR de VSAPI 08 Jan 2021

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

Search and delete AUTORUN.INF files created by Trojan.INF.HIDDENTEAR.THAOGBA that contain these strings

[ Learn More ]
  • [version]
    Signature=$chicago$
    AdvancedINF=2.5

    [DefaultInstall]
    CustomDestination=CustInstDestSectionAllUsers
    RunPreSetupCommands=RunPreSetupCommandsSection

    [RunPreSetupCommandsSection]
    ; Commands Here will be run Before Setup Begins to install
    cmd /c start "C:\Windows\temp\{Random Characters}.exe"
    taskkill /IM cmstp.exe /F

    [CustInstDestSectionAllUsers]
    49000,49001=AllUSer_LDIDSection, 7

    [AllUSer_LDIDSection]
    "HKLM", "SOFTWARE\Microsoft\Windows\CurrentVersion\App Paths\CMMGR32.EXE", "ProfileInstallPath", "%UnexpectedError%", ""

    [Strings]
    ServiceName="Crimson"
    ShortSvcName="Crimson"

Step 3

Scan your computer with your Trend Micro product to delete files detected as Trojan.INF.HIDDENTEAR.THAOGBA. 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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