Filtragem de com RedHat Linux

Apresentação em tema: "Filtragem de com RedHat Linux"— Transcrição da apresentação:

1 Filtragem de Email com RedHat Linux
Ruben Oliveira RHCE RHCX MCSE MCITP 1

2 SMTP - Simple Mail Transfer Protocol A evolução do SPAM Spam Bad Guys
Conteúdos RedHat Linux SMTP - Simple Mail Transfer Protocol A evolução do SPAM Spam Bad Guys DNS Block Lists SPF Sender ID DomainKeys Greylisting Pattern Rules Bayes DCC Pyzor Razor OCR AV Soluções de Segurança 2

3 Linux Origins 1984: The GNU Project and the Free Software Foundation
Creates open source version of UNIX utilities Creates the General Public License (GPL)‏ 1991: Linus Torvalds Creates open source, UNIX-like kernel, released under the GPL Today: Linux kernel + GNU utilities = complete, open source, UNIX- like operating system Packaged for targeted audiences as distributions 3

4 Red Hat Enterprise Linux Enterprise-targeted operating system
Focused on mature open source technology 18-24 month release cycle Certified with leading OEM and ISV products Purchased with one year Red Hat Network subscription and support contract Support available for seven years after release Up to 24x7 coverage plans available 4

5 Red Hat sponsored open source project
The Fedora Project Red Hat sponsored open source project Focused on latest open source technology Rapid four to six month release cycle Available as free download from the Internet CentOS Created from the RedHat Linux OpenSource Software No Support from RedHat Community Supported Rebranded RHEL Clone without the trademarks or RHN 5

6 SMTP (Simple Mail Transfer Protocol)‏ protocolo baseado em texto
Protocolo funciona na porta 25 numa rede TCP. Simples : telnet servidor 25 6

7 Exemplo de uma sessão SMTP
telnet smpt.dominio.pt 25 S: 220 smtp.dominio.pt ESMTP Postfix C: HELO dominio2.pt S: 250 Hello dominio2.pt C: MAIL FROM: S: 250 Ok C: RCPT TO: C: DATA S: 354 End data with <CR><LF>.<CR><LF> C: Subject: Mensagem de Teste C: C: Olá. C: . S: 250 Ok: queued as 12345 C: quit S: 221 Bye 7

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9 Qual a razão do email comercial não solicitado ser conhecido como SPAM ?
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10 spiced ham famoso na 2ª guerra mundial Monty Python sketch 1970 menu
SPAM spiced ham famoso na 2ª guerra mundial Monty Python sketch 1970 menu 10

11 The Evolution of Spam The development of spammer techniques
Direct mailing Spammers Ingénuos Fácil de Filtrar Open Relay Erro de configuração Zombie or bot networks - Internet popular - Updates ou Anti Virus deficientes - Utilizadores ingénuos 11

12 The Evolution of Spam The development of spam content
Simple text and HTML Personalised mail Random text strings Graphics or PDF 12

13 Empresas de Marketing Directo
Afirmam que só enviam s com o consentimento do destinatário. Como exemplo, Target, Virid, VirtualTarget, BrasilBiz, Spinletter.net 13

14 Marketers Jeanne Jennings is a leading authority and independent consultant with over 15 years of experience in the and online realm. She specializes in all aspects of marketing and publishing, from strategy through design and metrics analysis. Jeanne works with medium- to enterprise-sized organizations and is expert at helping her clients become more effective and more profitable online. She is the author of "The Marketing Kit: The Ultimate Marketer’s Bible" (SitePoint, 2007) and publisher of "The Jennings Report," a free newsletter for online marketing professionals. Visit her online at JeanneJennings.com. 14

15 march folded the wavy chestnut lock, andnot buy it back; and faith in one another madethe students pay some money for the dance? cloud of pink and white lace that lay upon have stared straight before you, utterly right, for i'm all in a tangle now with doubts then the mournful 15

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17 http://www. darknet. org
The 41-count indictment, unsealed in a Detroit federal court, claims Ralsky, 52, and his fellow defendants operated a wide-ranging international fraud scheme involving millions of illegal s touting thinly-traded Chinese penny stocks. Ralsky profited by selling the stock at artificially inflated prices. Only two of the defendants appeared in court Jan. 3 for arraignment. Ralsky is reportedly at large in Europe. According to the indictment, Ralsky and his group earned approximately $3 million on the scheme during the summer of Ralsky faces charges including conspiracy, fraud in connection with electronic mail, computer fraud, mail fraud, wire fraud and money laundering. The illegal practices cited in the indictment include evading spam- blocking devices, falsifying headers and domain names, using proxy computers to distribute the spam and misrepresenting the advertising content in the actual . 17

18 Inside the "Ron Paul" Spam Botnet
SecureWorks would like to thank our colleagues at myNetWatchman, IronPort and Spamhaus for their invaluable assistance in the investigation of this botnet. Tracking the Spam headers vary but some static elements The Reactor Core written in the Python language. Examining these showed that the Srizbi botnet is actually a working component of a piece of spamware known as “Reactor Mailer”. Reactor Mailer has been around at least since 2004, and is in its third major version. It was created along with Srizbi, the bot that actually does the mailing. Reactor Mailer is the brainchild of a spammer who goes by the pseudonym “spm”. He calls his company “Elphisoft”, and has even been interviewed about his operation by the Russian hacker website xakep.ru. 18

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20 Spamit is the alternate name for the Glavmed sponsorship, responsible for lots of illegal spamming of Canadian Pharmacy and US Pharmacy websites. Following the same example as SanCash and GenBucks, this follows the pattern of having a public-facing, wide-open entity (ie: GenBucks / Glavmed) which makes no mention of spamming, or hijacking of servers, coupled with a very secretive, underground Affiliate program (ie: SanCash / Spamit) which is invitation only, password protected, and never mentioned anywhere in public, via any means. 20

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23 Dark Mailer What is ROKSO? The Register of Known Spam Operations (ROKSO) is a register of spam senders and spam services that have been thrown off Internet Service Providers 3 times or more in connection with spamming or providing spam services, and are therefore repeat offenders. Spamhaus believes that these known determined professional spam operations are responsible for approximately 80% of spam on the Internet. 23

24 Planeamento e Gestão da Filtragem de Email
Filtragem de conexões Filtragem por análise de conteúdo 24

25 Spamhaus Zen SBL XBL PBL
DNSBL DNS Block List Spamhaus Zen SBL XBL PBL identificam IPs que foram usados para envio de SPAM alvo de tentativas de DoS 25

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27 * PSBL (psbl.surriel.com)‏ * FIVETEN (blackholes.five-ten-sg.com)‏
* PSBL (psbl.surriel.com)‏ * FIVETEN (blackholes.five-ten-sg.com)‏ * ZEN (zen.spamhaus.org)‏ * APEWS ( * SORBS (dnsbl.sorbs.net)‏ * Spamcop (bl.spamcop.net)‏ * CBL (cbl.abuseat.org)‏ * korea.services.net * UBL (ubl.unsubscore.com)‏ 27

28 Sender Policy Framework ou "Estrutura de Politicas de Remetente"
Para que Serve ? Identificar os servidores legítimos que podem enviar de um domínio. Como se configura ? No servidor de DNS num record TXT Ex: IN TXT "v=spf1 mx -all" todos os MX do dominio são os únicos que devem enviar Cabe ao servidor receptor a recusa ou não de processar o 28

29 Patrocinado pela Microsoft semelhante ao Sender Policy Framework
Sender ID Patrocinado pela Microsoft semelhante ao Sender Policy Framework Purported Responsible Address 29

30 When the recipient gets the message, they'll be able to:
DomainKeys Yahoo When the recipient gets the message, they'll be able to: verify the domain name of the sender. confirm the message content hasn't been altered. match the "from" address to the sender's domain name to prevent forgeries. trace the message back to the sender's domain name. 30

31 Temporáriamente rejeita mensagem
Greylisting Temporáriamente rejeita mensagem Vantagens Fácil implementar Pouco CPU comparado com outras técnicas Desvantagens O primeiro pode demorar SMTP, Instant Messaging, Push Mail 31

32 Regras Spamassassin body LOCAL_DEMONSTRATION_RULE /test/
score LOCAL_DEMONSTRATION_RULE 0.1 describe LOCAL_DEMONSTRATION_RULE This is a simple test rule header LOCAL_DEMONSTRATION_SUBJECT Subject =~ /\btest\b/i score LOCAL_DEMONSTRATION_SUBJECT 32

33 analisa conteúdos que lhe indicam como email legitimo ou spam
Bayesian classifier analisa conteúdos que lhe indicam como legitimo ou spam e “aprende” 33

34 Distributed signature systems Pyzor Razor DCC
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35 Motores OCR gratuitos: gocr,ocrad CPU intensive HTML table slice
Fácil Instalar Motores OCR gratuitos: gocr,ocrad CPU intensive HTML table slice 35

36 MailScanner Supported
AntiVirus Free Clamav BitDefender MailScanner Supported # sophos from or # mcafee from or # command from or # bitdefender from or # drweb from or # kaspersky from or # etrust from or # inoculate from or # inoculan from ftp.ca.com/pub/getbbs/linux.eng/inoctar.LINUX.Z, or # nod for No32 before version 1.99 from or # f-secure from or # f-prot from or # panda from or # rav from or # antivir from or # clamav from or # trend from or # norman from or # css from or # avg from or # vexira from or # symscanengine from (Symantec Scan Engine, not CSS)‏ 36

37 IMF Inteligent Message Filtering * Content Filtering
Exchange Anti-Spam : Sender ID IMF Inteligent Message Filtering * Content Filtering * IP Allow and Block List Provider * Sender Filtering * Sender Reputation * SMTP Tarpiting 37

38 Forefront Security 38

39 Soluções Anti Spam Comerciais
Sonicwall grupo Rumos GFI MailEssential Barracuda IPBrick EdgeBox AnubisNetwork 39

40 Spam will be a thing of the past in two years' time, Microsoft boss Bill Gates has promised. January 2004 40

41 Organizações que combatem o spam
Cauce (coallition against unsolicited commercial )‏ 41

42 NENHUMA técnica anti-spam funciona bem sozinha.
Concluindo, NENHUMA técnica anti-spam funciona bem sozinha. Os spammers estão sempre a inovar as suas técnicas, e precisamos modernizar as nossas proprias técnicas de bloqueio. Serviço tem importância vital na maioria das empresas. O Spam pode ser reduzido a um mínimo aceitável. Actualização Constante ! No software já usado e com implementação de novas tecnologias. 42

43 Cursos: RH033 Red Hat Linux Essentials
RH133 Red Hat Linux System Administration RH253 Red Hat Linux Network Services and Security Administration 43

44 Case Study I - PT Inovação Case Study II - Divultec
Obrigado Coffee Break Case Study I - PT Inovação Case Study II - Divultec 44