Advanced Topics of Mail Service
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Fighting Spam
Fighting Spam 2017-10-18 Dianne Skoll Roaring Penguin Software Inc. [email protected] www.roaringpenguin.com Approaches to Fighting Spam ● Reputation-Based (IP, Domain) ● Authentication (SPF, DKIM, DMARC) ● Behavior-Based (greylisting, botnet detection) ● Content-Based ● Defense in Depth www.roaringpenguin.com IP Reputation ● Typically implemented by DNSBLs. ● Reactive – IPs are listed only after they spam. ● Some DNSBLs are high-quality. Most are not. ● Few are transparent as to listing and delisting criteria. ● Few have good IPv6 coverage. ● Useful as a first pass to cut down on spam passing to the rest of the filtering stages. www.roaringpenguin.com Domain Reputation ● Also typically implemented by DNSBLs. ● Reactive. ● Low to moderate hit rate. ● May be applied to sending domain and/or to domains of URLs in the message body. www.roaringpenguin.com Domain Reputation - 2 ● Spammers often register throwaway domains as sending domains. ● Idea: Penalize messages from “newly-seen” domains. ● CanIt 10.1.7 tracks domains seen across all CanIt installations and permits you to (mildly) penalize mail from only-recently-seen domains. www.roaringpenguin.com Authentication: SPF ● SPF (Sender Policy Framework) is a mechanism whereby domain owners can declare which machines may send email on their domains’ behalf. ● For arbitrary domains, an SPF “pass” is a mild spam indicator! ● Spammers are better at setting up SPF than many legitimate administrators. www.roaringpenguin.com Authentication: SPF - 2 ● SPF is useful for trusted domains (banks, PayPal, eBay, etc.) ● Adding points on SPF “fail” or “softfail” is useful. ● Subtracting points on SPF “pass” for arbitrary domains is dangerous. ● Subtracting points on SPF “pass” for trusted domains is useful. -
DMARC — Defeating E-Mail Abuse
CERT-EU Security Whitepaper 17-001 DMARC — Defeating E-Mail Abuse Christos Koutroumpas ver. 1.3 February 9, 2017 TLP: WHITE 1 Preface E-mail is one of the most valuable and broadly used means of communication and most orga- nizations strongly depend on it. The Simple Mail Transport Protocol (SMTP) – the Internet’s underlying email protocol – was adopted in the eighties and is still in use after 35 years. When it was designed, the need for security was not so obvious, and therefore security was not incor- porated in the design of this protocol. As a result, the protocol is susceptible to a wide range of attacks. Spear-phishing campaigns in particular can be more successful by spoofing (altering) the originator e-mail address to imper- sonate a trusted or trustworthy organization or person. This can lead to luring the recipient into giving away credentials or infecting his/her computer by executing malware delivered through the e-mail. While raising user awareness on how to avoid e-mail fraud is recommended, the Verizon Data Breach Investigations Report indicates that more needs to be done. The DBIR report reveals that 30% of all phishing e-mail messages were opened by the recipients and with 12% clicked on the content and executed malicious code. The median time for the first user of a phishing campaign to open the malicious email is 1 minute, 40 seconds. The median time to the first click on the attachment was 3 minutes, 45 seconds. These statistics highlight the risk for an organization on the receiving end of spear-phishing e-mails. -
Electronic Mail Standard
IT Shared Services Standard: Electronic Mail Standard For South Carolina State Agencies Version 1.0 Effective: August 8, 2018 Revision History: Date Authored by Title Ver. Notes Recommended by the Security and Architecture 08.08.2018 Standards 1.0 Executive Oversight Group. Review Board Standard finalized. Electronic Mail Standard | 2 Contents Revision History: ................................................................................................................................... 1 Electronic Mail ...................................................................................................................................... 4 Rationale ........................................................................................................................................... 4 Agency Exception Requests ............................................................................................................... 4 Current State..................................................................................................................................... 4 Purchasing......................................................................................................................................... 4 Maintenance ..................................................................................................................................... 5 Service Level Agreements ............................................................................................................. 5 Security ............................................................................................................................................ -
Sicherer Betrieb Von E-Mail-Servern (Isi-S)
Sicherer Betrieb von E-Mail-Servern (ISi-Mail-Server) BSI-Studie zur Internet-Sicherheit (ISi-S) Version 1.0 ISi-Reihe ISi-S Sicherer Betrieb von E-Mail-Servern Vervielfältigung und Verbreitung Bitte beachten Sie, dass das Werk einschließlich aller Teile urheberrechtlich geschützt ist. Erlaubt sind die Vervielfältigung und Verbreitung zu nicht-kommerziellen Zwecken, insbesondere zu Zwecken der Ausbildung, Schulung, Information oder hausinternen Bekanntmachung, sofern sie unter Hinweis auf die ISi-Reihe des BSI als Quelle erfolgen. Dies ist ein Werk der ISi-Reihe. Ein vollständiges Verzeichnis der erschienenen Bände findet man auf den Internet-Seiten des BSI. http://www.bsi.bund.de oder http://www.isi-reihe.de Bundesamt für Sicherheit in der Informationstechnik ISi-Projektgruppe Postfach 20 03 63 53133 Bonn Tel. +49 (0) 228 99 9582-0 E-Mail: [email protected] Internet: http://www.bsi.bund.de © Bundesamt für Sicherheit in der Informationstechnik 2009 2 Bundesamt für Sicherheit in der Informationstechnik ISi-Reihe ISi-S Sicherer Betrieb von E-Mail-Servern Vorwort Liebe Leserinnen und Leser, immer mehr Prozesse verlagern sich in die virtuelle Welt des Internets: Kommunikation und Daten- austausch erfolgen per E-Mail, Bankgeschäfte und Einkäufe werden zunehmend online getätigt. Dabei müssen häufig persönliche und vertrauliche Daten über das Internet versendet werden. Diese sind ein attraktives und lukratives Ziel für Online-Kriminelle, die heute international organisiert und professionell strukturiert zusammen arbeiten. IT-Kriminalität ist für die Angreifer ein lohnenswertes Geschäft bei vergleichsweise niedrigem Risiko. Identitätsdiebstahl und Angriffe mit Schadprogram- men unterschiedlichster Art gehören bei der Nutzung des Internets zu den ernstzunehmenden Bedrohungen für alle Anwender. -
Design and Management of Email Service
Design and Management of Email Service Source : homepage.ntu.edu.tw/~jsc/2005-mail.ppt Outline Introduction to the architecture and operation of SMTP Design of a suitable email system – Webmail solutions Postfix and simple configuration samples Spam and virus filtering Conclusion 2 Overview Electronic mail service has already evolved into one of the major Internet applications. It is not only fundamental, but also a must. Users may become impatient when mails were delayed, not to mention failed to access their emails. – Imagine we meet the situation of power failure or cut of water supply 3 Architecture of a Simple Mail System Consists of the following components – MTA - Mail transfer agent Sending and forwarding emails Server end – MDA - Mail delivery agent Delivering emails to recipients’ mailbox Server end – Pop3/Imap4 Daemons For users to download their mailboxs Server end – MUA - Mail user agent Reading and composing emails 4 Client end Architecture of a Simple Mail System Protocols Used for Mail System Protocols – For computer programs to communicate with each other – Similar to languages that human beings speak SMTP – Simple Mail Transfer Protocol – Too simple to provide any “advanced features” Authentication Authorization POP3 – Post Office Protocol version 3 – Simple IMAP4 – Internet Message Access Protocol version 4 – Fully compatible with internet message standards, e.g. MIME. – Allow messages to be accessed from more than one computer. – Provide support for online, offline, and disconnected modes. 6 – Multiple and share folders. Mail Forwarding Between Servers How to Find the Way to the Destination? How do we find the way to [email protected]? 8 DNS: The Key to All Internet Services Query DNS server by the address part of email address.([email protected]) 1. -
Delivering Results to the Inbox Sailthru’S 2020 Playbook on Deliverability, Why It’S Imperative and How It Drives Business Results Introduction to Deliverability
Delivering Results to the Inbox Sailthru’s 2020 Playbook on Deliverability, Why It’s Imperative and How It Drives Business Results Introduction to Deliverability Every day, people receive more than 293 billion Deliverability is the unsung hero of email marketing, emails, a staggering number that only represents ultimately ensuring a company’s emails reach their the tip of the iceberg. Why? The actual number intended recipients. It’s determined by a host of of emails sent is closer to 5.9 quadrillion, with the factors, including the engagement of your subscribers overwhelming majority blocked outright or delivered and the quality of your lists. All together, these factors to the spam folder. result in your sender reputation score, which is used to determine how the ISPs treat your email stream. Something many people don’t realize is that to the Deliverability is also a background player, so far in the major Internet Service Providers (ISPs) — Gmail, shadows that many people don’t think about it, until Yahoo!, Hotmail, Comcast and AOL — “spam” there’s a major issue. doesn’t refer to marketing messages people may find annoying, but rather malicious email filled with That’s why Sailthru’s deliverability team created this scams and viruses. In order to protect their networks guide. Read on to learn more about how deliverability and their customers, the ISPs cast a wide net. If a works on the back-end and how it impacts revenue, message is deemed to be spam by the ISP’s filters, it’s your sender reputation and how to maintain a good dead on arrival, never to see the light of the inbox, as one, and best practices for list management, email protecting users’ inboxes is the top priority of any ISP. -
Presentations Made by Senders
SES ���� ��� � �� � � � � � � � ������������� DomainKeys ��������� SPF ��������������������� ���������� ����������������� ������������������������������������������������ Contents Introduction 3 Deployment: For Email Receivers 6 Audience 3 Two Sides of the Coin 6 How to Read this White Paper 3 Recording Trusted Senders Who Passed Authentication 6 A Vision for Spam-Free Email 4 Whitelisting Incoming Forwarders 6 The Problem of Abuse 4 What To Do About Forgeries 6 The Underlying Concept 4 Deployment: For ISPs and Enterprises 7 Drivers; or, Who’s Buying It 4 Complementary considerations for ISPs 7 Vision Walkthrough 5 Deployment: For MTA vendors 8 About Sender Authentication 8 Which specification? 8 An Example 8 Conformance testing 8 History 8 Perform SRS and prepend headers when forwarding 8 How IP-based Authentication Works 9 Add ESMTP support for Submitter 8 The SPF record 9 Record authentication and policy results in the headers 8 How SPF Classic Works 9 Join the developers mailing list 8 How Sender ID works 9 Deployment: For MUA vendors 9 How Cryptographic Techniques Work 0 Displaying Authentication-Results 9 Using Multiple Approaches Automatic switching to port 587 9 Reputation Systems Deployment: For ESPs 20 Deployment: For Email Senders 2 Don’t look like a phisher! 20 First, prepare. 2 Delegation 20 Audit Your Outbound Mailstreams 2 Publish Appropriately 20 Construct the record 2 Deployment: For Spammers 2 Think briefly about PRA and Mail-From contexts. 3 Two Types of Spammers 2 Test the record, part 3 Publish SPF and sign with DomainKeys. 2 Put the record in DNS 3 Stop forging random domains. 2 Test the record, part 2 4 Buy your own domains. 2 Keep Track of Violations 4 Reuse an expired domain. -
Combatting Spam Using Mimedefang, Spamassassin and Perl
Combating Spam Using SpamAssassin, MIMEDefang and Perl Copyright 2003 David F. Skoll Roaring Penguin Software Inc. (Booth #23) Administrivia Please turn off or silence cell phones, pagers, Blackberry devices, etc... After the tutorial, please be sure to fill out an evaluation form and return it to the USENIX folks. 2 Overview After this tutorial, you will: Understand how central mail filtering works. Know how to use MIMEDefang to filter mail. Be able to integrate SpamAssassin into your mail filter. Know how to implement mail filtering policies with MIMEDefang and Perl. Know how to fight common spammer tactics. 3 Outline Introduction to Mail Filtering Sendmail's Milter API MIMEDefang Introduction, Architecture Writing MIMEDefang Filters SpamAssassin Integration Advanced Filter Writing Fighting Common Spammer Tactics Advanced Topics Policy Suggestions 4 Assumptions I assume that you: Are familiar with Sendmail configuration. You don't need to be a sendmail.cf guru, but should know the basics. Are familiar with Perl. Again, you don't need to be able to write an AI program in a Perl one- liner, but should be able to read simple Perl scripts. Are running the latest version of Sendmail 8.12 on a modern UNIX or UNIX-like system. 5 Why Filter Mail? The old reason: to stop viruses. The new reason: to stop spam and inappropriate content. Blocking viruses is easy. Block .exe and similar files, and test against signature databases. Blocking spam is hard, but becoming increasingly important. Organizations can even face lawsuits over inappropriate content. 6 Mail filtering is required for many reasons. In addition to the reasons given on the slide, you might need to filter outgoing mail as well to prevent virus propagation, dissemination of sensitive information, etc. -
Account Administrator's Guide
ePrism Email Security Account Administrator’s Guide - V10.4 4225 Executive Sq, Ste 1600 Give us a call: Send us an email: For more info, visit us at: La Jolla, CA 92037-1487 1-800-782-3762 [email protected] www.edgewave.com © 2001—2016 EdgeWave. All rights reserved. The EdgeWave logo is a trademark of EdgeWave Inc. All other trademarks and registered trademarks are hereby acknowledged. Microsoft and Windows are either registered trademarks or trademarks of Microsoft Corporation in the United States and/or other countries. Other product and company names mentioned herein may be the trademarks of their respective owners. The Email Security software and its documentation are copyrighted materials. Law prohibits making unauthorized copies. No part of this software or documentation may be reproduced, transmitted, transcribed, stored in a retrieval system, or translated into another language without prior permission of EdgeWave. 10.4 Contents Chapter 1 Overview 1 Overview of Services 1 Email Filtering (EMF) 2 Archive 3 Continuity 3 Encryption 4 Data Loss Protection (DLP) 4 Personal Health Information 4 Personal Financial Information 5 Document Conventions 6 Other Conventions 6 Supported Browsers 7 Reporting Spam to EdgeWave 7 Contacting Us 7 Additional Resources 7 Chapter 2 Portal Overview 8 Navigation Tree 9 Work Area 10 Navigation Icons 10 Getting Started 11 Logging into the portal for the first time 11 Logging into the portal after registration 12 Changing Your Personal Information 12 Configuring Accounts 12 Chapter 3 EdgeWave Administrator -
Set up Mail Server Documentation 1.0
Set Up Mail Server Documentation 1.0 Nosy 2014 01 23 Contents 1 1 1.1......................................................1 1.2......................................................2 2 11 3 13 3.1...................................................... 13 3.2...................................................... 13 3.3...................................................... 13 4 15 5 17 5.1...................................................... 17 5.2...................................................... 17 5.3...................................................... 17 5.4...................................................... 18 6 19 6.1...................................................... 19 6.2...................................................... 28 6.3...................................................... 32 6.4 Webmail................................................. 36 6.5...................................................... 37 6.6...................................................... 38 7 39 7.1...................................................... 39 7.2 SQL.................................................... 41 8 43 8.1...................................................... 43 8.2 strategy.................................................. 43 8.3...................................................... 44 8.4...................................................... 45 8.5...................................................... 45 8.6 Telnet................................................... 46 8.7 Can postfix receive?.......................................... -
What Is DMARC, SPF, and DKIM? • How to Configure • Common Mistakes • Best Practices • How Phishes Get By
How to Prevent 81% of Phishing Attacks From Sailing Right Through DMARC, SPF, and DKIM Roger A. Grimes Data-Driven Defense Evangelist [email protected] About Roger • 30 years plus in computer security • Expertise in host and network security, IdM, crypto, PKI, APT, honeypot, cloud security • Consultant to world’s largest companies and militaries for decades • Previous worked for Foundstone, McAfee, Microsoft • Written 11 books and over 1,000 magazine articles • InfoWorld and CSO weekly security columnist since 2005 • Frequently interviewed by magazines (e.g. Newsweek) and radio shows (e.g. NPR’s All Things Considered) Roger A. Grimes Certification exams passed include: Data-Driven Defense Evangelist KnowBe4, Inc. • CPA • CISSP Twitter: @RogerAGrimes • CISM, CISA LinkedIn: https://www.linkedin.com/in/rogeragrimes/ • MCSE: Security, MCP, MVP • CEH, TISCA, Security+, CHFI • yada, yada Roger’s Books 3 KnowBe4, Inc. • The world’s most popular integrated Security Awareness Training and Simulated Phishing platform • Based in Tampa Bay, Florida, founded in 2010 • CEO & employees are ex-antivirus, IT Security pros • 200% growth year over year • We help tens of thousands of organizations manage the problem of social engineering 4 Today’s Presentation • What is DMARC, SPF, and DKIM? • How to Configure • Common Mistakes • Best Practices • How Phishes Get By 5 • What is DMARC, SPF, and DKIM? § How to Configure Agenda • Best Practices • How Phishes Get By 6 DMARC, DKIM, SPF Global Phishing Protection Standards • Sender Policy Framework (SPF) • Domain -
A Security Analysis of Email Communications
A security analysis of email communications Ignacio Sanchez Apostolos Malatras Iwen Coisel Reviewed by: Jean Pierre Nordvik 2 0 1 5 EUR 28509 EN European Commission Joint Research Centre Institute for the Protection and Security of the Citizen Contact information Ignacio Sanchez Address: Joint Research Centre, Via Enrico Fermi 2749, I - 21027 Ispra (VA), Italia E-mail: [email protected] JRC Science Hub https://ec.europa.eu/jrc Legal Notice This publication is a Technical Report by the Joint Research Centre, the European Commission’s in-house science service. It aims to provide evidence-based scientific support to the European policy-making process. The scientific output expressed does not imply a policy position of the European Commission. Neither the European Commission nor any person acting on behalf of the Commission is responsible for the use which might be made of this publication. All images © European Union 2015, except: Frontpage : © bluebay2014, fotolia.com JRC 99372 EUR 28509 EN ISSN 1831-9424 ISBN 978-92-79-66503-5 doi:10.2760/319735 Luxembourg: Publications Office of the European Union, 2015 © European Union, 2015 Reproduction is authorised provided the source is acknowledged. Printed in Italy Abstract The objective of this report is to analyse the security and privacy risks of email communications and identify technical countermeasures capable of mitigating them effectively. In order to do so, the report analyses from a technical point of view the core set of communication protocols and standards that support email communications in order to identify and understand the existing security and privacy vulnerabilities. On the basis of this analysis, the report identifies and analyses technical countermeasures, in the form of newer standards, protocols and tools, aimed at ensuring a better protection of the security and privacy of email communications.