Intro aos ataques superiores de hoje de Botnet

por Corey Nachreiner, CISSP, Analista de segurança da rede, tecnologias de WatchGuard

[Nota do editor: Este artigo suplementa a lista dos ataques mostrados na parte 2 da série video, Análise de Malware: Botnets. De “análise Malware: Botnets, peça 2 mostras que do ″ um subconjunto pequeno do botnet ataca na ação. Este artigo enche-se para fora que o subconjunto com mais ataca encontrado geralmente em um arsenal dos herder do bot. Os subscritores de LiveSecurity podem encontrar os videos, livres da carga, no nosso Tutorials video página. –Scott]

Você ouvirá frequentemente os botnets descritos como a faca suíça do exército de um “hacker.” Apenas enquanto uma faca suíça do exército pode vir com uma variedade louca das lâminas, da tesoura, e das chaves de fenda, os bots vêm com façanhas e comandos numerosos que permitem que os herders do bot lancem muitos tipos diferentes de ataques.

Desde codificar acima das tomadas tempo e habilidade de um cliente do bot, a maioria de atacantes compram o código do bot no subterrâneo em linha. Os bots maliciosos populares incluem Phatbot, Agobot, e esse mostrado em nosso vídeo, Rxbot. Estes clientes do bot usam o código modular, assim que se um herder do bot não amar a disposição dos comandos suas ofertas do bot, adiciona simplesmente novos. Para exemplos, leia sobre.

Que se emparelha mais melhor do que zombis e Spam?

Os herders do Bot leverage geralmente seus bots como relés enormes do Spam. Como enorme? De acordo com um estudo recente por Commtouch, 87% de todo o email emitido sobre o Internet durante 2006 era Spam. Esta e-sucata gerou o Terabyte até 1700 (1.700.000.000 megabytes) do tráfego do Internet diário. Botnets gerou 85% desse Spam, uma onda tidal de correio não desejado.

A maioria de código do bot vem com pelo menos alguns comandos fazer o Spamming mais fácil. Alguns bots optimized mesmo especificamente para o Spamming. Um herder do bot que usa Phatbot pode emitir o comando harvest.emails para coletar cada email address no computador de uma vítima. Se um botnet dos herder de Phatbot consistir em milhares de máquinas da vítima, ele poderia rapidamente e fàcilmente criar listas do email de soldado-normous ao Spam mais atrasado.

Agobot customized para o Spamming. Inclui mesmo seu próprio motor do smtp de modo que possa Spam diretamente. Seus comandos do Spamming do email permitem que um herder de Agobot diga cada um de computadores da sua vítima:

• Download uma lista de endereços do email ao Spam
• Download uma mensagem do email do molde para emitir para fora
• O começo emitindo para fora a usar-se das mensagens muito o email diferente enfía simultaneamente
• Comece e pare o Spamming quando instruído a.

O bot em nosso vídeo, Rxbot, não é considerado um Spamming bot. Entretanto, mesmo contem um comando elementar que permita que um herder do bot emita um email de todas suas vítimas do 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. #