Introducción a los ataques superiores de hoy de Botnet

por Corey Nachreiner, CISSP, Analista de seguridad de la red, tecnologías de WatchGuard

[Nota del redactor: Este artículo suple la lista de los ataques demostrados en la parte 2 de la serie video, Análisis de Malware: Botnets. “Análisis de Malware: Botnets, pieza 2 demostraciones del ″ que un subconjunto pequeño de botnet ataca en la acción. Este artículo completa que el subconjunto con más ataca encontrado comúnmente en un arsenal de los herder del BOT. Los suscriptores de LiveSecurity pueden encontrar los videos, gratuitamente, en nuestro Clases particulares video página. –Scott]

Usted oirá a menudo los botnets descritos como cuchillo suizo del ejército “de un hacker.” Apenas mientras que un cuchillo suizo del ejército puede venir con una variedad loca de láminas, de tijera, y de destornilladores, los bots vienen con las hazañas y los comandos numerosos que permiten que los herders del BOT lancen muchos diversos tipos de ataques.

Desde la codificación encima de las tomas tiempo y habilidad de un cliente del BOT, la mayoría de los atacantes compran código del BOT en el subterráneo en línea. Los bots malévolos populares incluyen Phatbot, Agobot, y el que está demostrado en nuestro vídeo, Rxbot. Estos clientes del BOT utilizan código modular, así que si un herder del BOT no ama el arsenal de comandos sus ofertas del BOT, él agrega simplemente nuevos. Por ejemplos, lea encendido.

¿Qué se aparea mejor que zombis y el Spam?

Los herders del BOT leverage comúnmente sus bots como relais enormes del Spam. ¿Cómo enorme? Según un estudio reciente de Commtouch, el 87% de todo el email enviado sobre el Internet durante 2006 eran Spam. Esta e-chatarra generó el Terabyte hasta 1700 (1.700.000.000 megabytes) del tráfico del Internet de diario. Botnets generó el 85% de ese Spam, una onda de marea del correo indeseado.

La mayoría del código del BOT viene con por lo menos algunos comandos de hacer el Spamming más fácil. Algunos bots incluso se optimizan específicamente para el Spamming. Un herder del BOT que usa Phatbot puede publicar el comando harvest.emails para recoger cada email address en la computadora de una víctima. Si un botnet de los herder de Phatbot consiste en millares de máquinas de la víctima, él podría crear rápidamente y fácilmente listas del email del soldado enrolado en el ejército-normous a un Spam más último.

Agobot se modifica para requisitos particulares para el Spamming. Incluso incluye su propio motor del smtp de modo que pueda Spam directamente. Sus comandos del Spamming del email permiten que un herder de Agobot diga cada uno de las computadoras de su víctima:

• Descargue una lista de las direcciones del email al Spam
• Descargue un mensaje del email de la plantilla para enviar
• El comienzo enviando usar de los mensajes mucho diverso email rosca simultáneamente
• Comience y pare el Spamming cuando está mandado a.

El BOT en nuestro vídeo, Rxbot, no se considera un Spamming BOT. Sin embargo, incluso contiene un comando elemental que permita que un herder del BOT envíe un email de todas sus víctimas del zombi.

I’m hiding behind my SOCKS

Many bots include a SOCKS server. SOCKS (an abbreviation for sockets) is a networking protocol designed to pass TCP traffic through a proxy server. In other words, if a client wanted to visit www.google.com using SOCKS, the client would send its request to a SOCKS server instead of to Google directly. The SOCKS server forwards that request to Google and returns the response to the client. However, to Google it looks as though the request came from the SOCKS server, not the actual client.

Bot herders love to use the SOCKS proxy to spam. A bot master simply enables the SOCKS proxy on one of his bots, then redirects his SOCKS-compatible, mass emailing program to the IP address of that bot. This causes the email program to send email using that bot as a relay. If an anti-spam program blacklists the bot’s IP address, the herder activates the SOCKS proxy on another bot, and his spam seems to originate from a new, clean IP address.

Furthermore, the bot herder can use a SOCKS proxy to anonymize just about any network traffic. And in Rxbot, for instance, activating the SOCKS proxy is simple: one six-letter command initiates all those anonymizing benefits.

Some bots have a Man-in-the-Middle

Bots also help herders launch Man-in-the-Middle (MitM) attacks. Most bots come with commands that allow their creators to redirect network traffic any way they like. For instance, a bot herder could tell a bot to redirect all its web traffic to his computer. Then, every time the unwitting victim (whose machine is hosting that bot) browses the Web, the attacker sees the traffic before forwarding it to its intended destination. This is one way bot masters capture sensitive information or steal login credentials.

Rxbot comes with the .redirect command. Herders can use this command to forward the network traffic destined for any TCP port, to any IP address they choose. Phatbot comes with additional redirect commands that allow it to forward GRE traffic, the special protocol used in establishing PPTP VPN connections. These examples merely hint at what a bot herder can accomplish with redirects.

Click Fraud and Poll Manipulation

Nowadays, the lure of illegal easy money motivates most bot herders. Our video shows how crooks can force their bots to click on revenue-generating Google ad words. As another example, Rxbot has a simple-yet-effective .visit command. If you send your bots this command, followed by a URL, they silently visit that URL. Here, silently is a technical term meaning the bot victim will not see her computer visit the URL. The visit happens in the background, without any web browser involvement. So, imagine you have 100,000 bots. With one command you could easily force all those bots to visit an online poll, vote, or game. If you wanted ToneDeaf UglyDork to win American Idol, you could command all your bots to visit the American Idol voting page and submit a vote. Since every vote would come from a different IP address, the results would look legitimate. And if the flaws in American e-voting aren’t fixed before 2008, bots just might elect ToneDeaf UglyDork as President, too.

Spam + IM = SPIM

Many IRC bots today have Instant Messenger (IM) and Peer-to-Peer (P2P) components in their attack arsenal. For instance, some bots allow you to send spam to IM channels (nicknamed SPIM ). Attackers commonly send malicious files or URLs to IM users, hoping to infect them with malware. Some bots incorporate commands that allow the bot herder to send these types of IM messages to his bots’ IM buddies. If those buddies then visit the URL or execute an attached file, they get infected with the herder’s bot and become minions in his botnet.

Some bots offer similar commands that help them spread via P2P applications. For instance, Agobot spreads by placing copies of itself in the share directories used by many popular P2P programs such as Kazaa and Limewire. The bot gives its file an enticing name, such as the title of a movie still in theaters. When someone downloads and runs this malicious trojan, their computer becomes another zombie.

Is it just me, or does it smell like bots in here?

In the video, we mentioned that many bots come with packet sniffers. Packet sniffers allow a bot master to see all of the network traffic that passes by his bots, and sometimes all the traffic that passes within the bot victim’s network as well. Attackers can learn a lot by sniffing a network. For instance, a bot herder might capture cleartext logins or see web cookies. They could even passively enumerate your infected network.

Agobot comes with some very advanced packet sniffing capabilities. Rather than sniffing and reporting every single packet, which creates volumes of junk for the herder to parse, Agobot allows a herder to sniff for specific strings or types of traffic. For example, you can command Agobot to capture all the web cookies it sees passing over a network. You can also specifically tell it to only sniff FTP, or IRC logins. In short, if something passes over a network in clear text, Agobot’s sniffing can pinpoint it.

Stay as sharp as the crooks

In our video and this article, we’ve listed the most common “Swiss Army blades” used in bots today. Since botnets are evolving fast, bots could have all-new blades tomorrow. For now, you can protect yourself best by understanding the threat — and following the defense measures we outline in “Malware Analysis: Botnets, Part 3.” Look for it on our Video Tutorials page beginning 17 October, 2007. #