Acelere su viaje SSE. Únase a Netskope en RSA.

  • Servicio de seguridad Productos Edge

    Protéjase contra las amenazas avanzadas y en la nube y salvaguarde los datos en todos los vectores.

  • Borderless SD-WAN

    Proporcione con confianza un acceso seguro y de alto rendimiento a cada usuario remoto, dispositivo, sitio y nube.

  • Plataforma

    Visibilidad inigualable y protección contra amenazas y datos en tiempo real en la nube privada de seguridad más grande del mundo.

Netskope ha sido nombrado Líder en el Informe del Cuadrante Mágico de Gartner™ 2022 en SSE

Obtenga el informe Todos los productos
Líder SSE Netskope gartner mq 2022
Respuesta rápida de Gartner®: ¿Cómo afecta la adquisición de Netskope a los proyectos SD-WAN, SASE y SSE?

Obtenga el informe
Gartner quick answer
Netskope ofrece una estrategia de seguridad cloud moderna, con capacidades unificadas para los datos y protección frente a amenazas, además de un acceso privado seguro.

Explora nuestra plataforma
Vista aérea de una ciudad metropolitana
Cambie a los servicios de seguridad en la nube líderes del mercado con una latencia mínima y una alta fiabilidad.

Más información
Lighted highway through mountainside switchbacks
Prevenga las amenazas que a menudo eluden otras soluciones de seguridad utilizando un marco SSE de un solo paso.

Más información
Lighting storm over metropolitan area
Soluciones de confianza cero para implementaciones de SSE y SASE

Más información
Boat driving through open sea
Netskope hace posible un proceso seguro, rápido y con inteligencia cloud para la adopción de los servicios en la nube, las aplicaciones y la infraestructura de nube pública.

Más información
Wind turbines along cliffside
  • Nuestros clientes

    Netskope da servicio a más de 2.000 clientes en todo el mundo, entre los que se encuentran más de 25 de las 100 empresas de Fortune

  • Soluciones para clientes

    Le apoyamos en cada paso del camino, garantizando su éxito con Netskope.

  • Formación y certificación

    La formación de Netskope le ayudará a convertirse en un experto en seguridad en la nube.

Ayudamos a nuestros clientes a estar preparados para cualquier situación

Ver nuestros clientes
Woman smiling with glasses looking out window
El talentoso y experimentado equipo de servicios profesionales de Netskope proporciona un enfoque prescriptivo para su exitosa implementación.

Más información
Servicios profesionales de Netskope
Asegure su viaje de transformación digital y aproveche al máximo sus aplicaciones en la nube, web y privadas con la capacitación de Netskope.

Más información
Group of young professionals working
  • Recursos

    Obtenga más información sobre cómo Netskope puede ayudarle a proteger su viaje hacia la nube.

  • Blog

    Descubra cómo Netskope permite la transformación de la seguridad y las redes a través del servicio de seguridad (SSE).

  • Eventos & Workshops

    Manténgase a la vanguardia de las últimas tendencias de seguridad y conéctese con sus pares.

  • Seguridad definida

    Todo lo que necesitas saber en nuestra enciclopedia de ciberseguridad.

Podcast Security Visionaries

Episodio 10: Construyendo relaciones de seguridad a través de la transparencia
In this episode, Mike and Andreas discuss aligning with works councils, forging business relationships through transparency, and embedding security into value streams.

Reproducir el pódcast
Building Security Relationships Through Transparency
Lea lo último sobre cómo Netskope puede hacer posible el viaje de confianza cero y SASE a través de las capacidades de SSE.

Lea el blog
Sunrise and cloudy sky
Netskope at RSA

Join Netskope at RSA Conference this year and be part of the real conversations on SASE and Zero Trust. Stop by our booth in South Hall, chat with an expert, register for our speaking sessions, and unwind by joining us at one of our events!

Más información
RSA logo
¿Qué es Security Service Edge (SSE)?

Explore el lado de la seguridad de SASE, el futuro de la red y la protección en la nube.

Más información
Four-way roundabout
  • Empresa

    Le ayudamos a mantenerse a la vanguardia de los desafíos de seguridad de la nube, los datos y la red.

  • Por qué Netskope

    La transformación de la nube y el trabajo desde cualquier lugar han cambiado la forma en que debe funcionar la seguridad.

  • Liderazgo

    Nuestro equipo de liderazgo está firmemente comprometido a hacer todo lo necesario para que nuestros clientes tengan éxito.

  • Partners

    Nos asociamos con líderes en seguridad para ayudarlo a asegurar su viaje a la nube.

Netskope posibilita el futuro del trabajo.

Descubra más
Curvy road through wooded area
Netskope está redefiniendo la seguridad de la nube, los datos y la red para ayudar a las organizaciones a aplicar los principios de Zero Trust para proteger los datos.

Más información
Switchback road atop a cliffside
Pensadores, constructores, soñadores, innovadores. Juntos, ofrecemos soluciones de seguridad en la nube de vanguardia para ayudar a nuestros clientes a proteger sus datos y usuarios.

Conozca a nuestro equipo
Group of hikers scaling a snowy mountain
La estrategia de venta centrada en el partner de Netskope permite a nuestros canales maximizar su expansión y rentabilidad y, al mismo tiempo, transformar la seguridad de su empresa.

Más información
Group of diverse young professionals smiling

RedLine Stealer Campaign Abusing Discord via PDF Links

Oct 03 2022

Resumen

RedLine is an infostealer malware discovered in 2020. Often sold in underground forums, it is capable of stealing data such as credit card numbers, passwords, VPN and FTP credentials, gaming accounts, and even data from crypto wallets. In May 2022, Netskope Threat Labs analyzed a RedLine stealer campaign that was using YouTube videos to spread, luring victims into downloading a fake bot to automatically buy Binance NFT Mystery Boxes. Later in 2022, this malware was also spotted being self-spread through YouTube videos that were advertising popular gaming hacking tools.

In September 2022, Netskope Threat Labs found a RedLine Stealer campaign being spread through phishing emails. The email lures the user into opening a PDF file that redirects the victim to a URL that downloads RedLine, hosted on Discord. 

Furthermore, we found that the attacker updated the same PDF file three times and didn’t flatten the latest version, which allowed us to retrieve three more URLs from older versions of the same file. These URLs download other malware from Discord, including PureCrypter and NjRAT (a.k.a. Bladabindi). NjRAT is another popular remote access trojan with many capabilities, such as logging keystrokes, stealing credentials from browsers, accessing the victim’s camera, managing files, and more.

In this blog post, we will analyze how this campaign works from the delivery method to the RAT payloads.

Delivery Method

The delivery method is fairly simple. The attacker sends a phishing email luring the user to open the attached PDF file, disguised as an invoice.

Phishing email that delivers RedLine.

The PDF file contains an image that shows a blurred document, luring the user into clicking on a download icon that downloads RedLine from Discord.

PDF Redirecting the user to a Discord URL, which downloads RedLine.

By analyzing the PDF, we found older versions of the same file with different URLs the attacker was using, which are still online and delivering other malware instead of RedLine, as we will see later in this post.

Older versions of the same PDF file containing different URLs.

This happens when the PDF is changed and isn’t flattened, keeping the update history within the objects.

RedLine Stealer

The latest URL in the PDF downloads a ZIP file from Discord that contains the RedLine Stealer payload, likely compiled on September 16, 2022.

RedLine Stealer payload

As we covered in our previous blog, RedLine does not execute if the following countries are detected:

  • Armenia
  • Azerbaiyán
  • Bielorrusia
  • Kazajstán
  • Kirguizistán
  • Moldova
  • Russia
  • Tayikistán
  • Ucrania
  • Uzbekistán
Blocklisted countries by RedLine Stealer.

RedLine Stealer is able to steal sensitive information from specific apps, such as Discord and Steam, as well as from browsers and FTP and VPN clients.

RedLine searching for Discord Tokens.

Furthermore, the latest version of RedLine is also able to steal data from cryptocurrency extensions on Google Chrome.

RedLine Stealer searching for Google Chrome extensions related to cryptocurrency.

This is the list of targeted Google Chrome extensions found in this specific sample:

  • AtomicWallet
  • Authenticator
  • BinanceChain
  • BitAppWallet
  • BoltX
  • BraveWallet
  • Coin98Wallet
  • Coinbase
  • EqualWallet
  • GuardaWallet
  • GuildWallet
  • HarmonyWallet
  • iWallet
  • JaxxxLiberty
  • KardiaChain
  • LiqualityWallet
  • MaiarDeFiWallet
  • MathWallet
  • Metamask
  • MewCx
  • NamiWallet
  • NiftyWallet
  • Oxygen
  • PaliWallet
  • Phantom
  • RoninWallet
  • SaturnWallet
  • TempleWallet
  • TerraStation
  • TonCrystal
  • Tronlink
  • Wombat
  • XdefiWallet
  • YoroiWallet

Lastly, we can find the RedLine Stealer C2 server and ID encrypted in its configuration. The data is base64 encoded and encrypted with a simple XOR algorithm using “Unhandier” as key.

RedLine Stealer configuration.

The decrypted C2 server address can be found in our GitHub repository.

Older versions of the same PDF

As previously mentioned, we found three additional URLs by analyzing the update history of the PDF. At the time of the analysis, all the URLs were still online and downloading other malware. 

Unlike RedLine Stealer, these other URLs were not downloading the final payload directly. Instead, they are downloading an HTA file (either directly or compressed) which is responsible for downloading and executing a payload, also hosted on Discord.

The first version of the PDF downloads a RAR file (“Invoice_NO355449609.rar”) with a compressed HTA file, which contains a Visual Basic Script that downloads the next stage payload (“Server.exe”) from Discord using bitsadmin.

First version of the PDF downloading a different malware.

The downloaded file (“Server.exe”) is NjRAT, which is a remote access trojan first spotted somewhere between 2013 and 2014.

NjRAT payload details.

This trojan provides remote access to infected machines, offering many functionalities such as access to the victim’s webcam, stealing credentials stored on browsers, and stealing keystrokes.

Part of NjRAT keylogger functionality.

Although this is not configured for this specific binary, there’s a feature that searches for Bitcoin addresses in the victim’s clipboard and replaces the value with the attacker’s address.

Feature to steal Bitcoins by replacing addresses in the clipboard.

This NjRAT payload is version 0.7d and it injects itself into a “svchost.exe” process.

NjRAT configuration variables.

The second and third version of the PDF works similarly to the first version, by downloading and executing an HTA file from Discord. The only difference between these versions is that the third one downloads the HTA file within a RAR (“Encrypted.rar”).

Second and third version of the PDF downloading another malware from Discord.

The downloaded file (“system.exe”) is PureCrypter, which is a malware loader commonly used to deliver other malware such as RedLine Stealer, AgentTesla, AsyncRAT, and others.

PureCrypter binary details.

This is a multi-stage malware that first runs PowerShell to sleep for 15 seconds and then loads the next stage from its own resources, which are compressed with gzip.

First stage of PureCrypter.

The next stage is highly obfuscated. Once running, it loads and decrypts a file from its resources using AES, which is a resource-only .NET binary that contains the final payload, which seems to be AgentTesla.

Second stage of PureCrypter loading the next payload.

Conclusiones

Attackers commonly target individuals with cheap remote access trojans, like RedLine Stealer, which can be found in underground forums for about $100 USD. Although these are simple attacks given the delivery method and types of malware, these kinds of threats can cause serious damage to individuals by stealing sensitive information, such as credit card numbers, website accounts, or cryptocurrency wallets. We strongly recommend individuals  avoid opening unknown files or clicking unknown links, especially if those were received by email. Also, using an antivirus endpoint solution could help as these are well known malware families.

Protección

Netskope Threat Labs is actively monitoring this campaign and has ensured coverage for all known threat indicators and payloads. 

  • Netskope Threat Protection
    • Win32.Trojan.RedLineStealer
    • Win32.Infostealer.RedLine
    • ByteCode-MSIL.Backdoor.Bladabhindi
    • ByteCode-MSIL.Trojan.AgentTesla
  • Netskope Advanced Threat Protection provides proactive coverage against this threat.
    • Gen.Malware.Detect.By.StHeur indicates a sample that was detected using static analysis
    • Gen.Malware.Detect.By.Sandbox indicates a sample that was detected by our cloud sandbox

IOCs

All the IOCs related to this campaign, scripts, and the Yara rules can be found in our GitHub repository.

author image
Gustavo Palazolo
Gustavo Palazolo is an expert in malware analysis, reverse engineering and security research, working many years in projects related to electronic fraud protection. He is currently working on the Netskope Research Team, discovering and analyzing new malware threats.