Sender Policy Framework (SPF) a Convention to Describe Hosts Authorized to Send SMTP Traffic
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
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 ............................................................................................................................................ -
What Is SPF? Introduction
Valimail White Paper February 2018 What is SPF? Introduction Sender Policy Framework (SPF) is a Work on SPF started in 2003, and domains cornerstone of email authentication, and is the have been deploying it increasingly widely first of several standards established for that since then. SPF was published as RFC 4408 purpose. in 2006, and became an officially proposed Internet standard via RFC 7208 in 2014. In a simplistic sense, SPF lets you create a whitelist for IP addresses. If a mail server SPF is widely used by major and minor with an IP address that’s not on your list tries receivers of email (Google, Microsoft, Yahoo, to send email using your domain, it won’t etc.) as well as all Secure Email Gateways pass the SPF authentication test. (SEGs). How It Works The way SPF works is quite simple in principle: For instance, we examined the SPF records for all 62 sponsors of the 2017 1. Domain owners publish SPF records to RSA Conference. We found 58 who had the Domain Name System (DNS) that spell published SPF records, but 17 of those out the rule sets for their domains. An had records with errors in them. That’s SPF record is plain text, and it can be a nearly 30 percent failure rate — and as simple as a single line listing the IP that’s among security companies. addresses that are allowed to send email on the domain’s behalf. Companies that don’t have a lot of expertise in cybersecurity in general (and email 2. When an email server receives an incoming security in particular) often find SPF email, it examines the domain shown in even more tricky. -
Electronic Mail
CSECSE 265:265: SystemSystem andand NetworkNetwork AdministrationAdministration ● Electronic Mail – Mail systems – Addressing, mail headers – Client/server philosophy, mail homes – Aliases, mail routing, mailing list software – sendmail – Security – Performance Spring 2016 CSE 265: System and Network Administration ©2004-2016 Brian D. Davison MailMail systemssystems ● Four components – Mail user agent (MUA) to read and compose mail – Mail transport agent (MTA) route messages – Delivery agent that stores messages for later retrieval by users – Optional access agent to connect user agent to message store Spring 2016 CSE 265: System and Network Administration ©2004-2016 Brian D. Davison TheThe bigbig picturepicture Spring 2016 CSE 265: System and Network Administration ©2004-2016 Brian D. Davison UserUser agentsagents ● Provide means to read and compose email – Outlook, Thunderbird, Eudora, pine, elm, IMP, /bin/mail, emacs, web-based gmail, and more ● Often have system-wide and personal configuration files ● Multipurpose Internet Mail Extensions (MIME) encoding for different text formats and attachments Spring 2016 CSE 265: System and Network Administration ©2004-2016 Brian D. Davison TransportTransport agentsagents ● Transport agents accept mail from a user agent, and deliver mail to the correct hosts – PMDF, postfix, smail, Exim, sendmail ● Speak the Simple Mail Transport Protocol (SMTP) or Extended SMTP (ESMTP) ● Run on port 25 (unencrypted) Spring 2016 CSE 265: System and Network Administration ©2004-2016 Brian D. Davison DeliveryDelivery agentsagents – Accepts mail from a transport agent, and delivers to the local recipient – Delivery can be to ● a person's mailbox ● a mailing list ● a file ● a program – Agents include ● /bin/mail for local users ● /bin/sh for programs ● /usr/bin/procmail for user-configurable delivery Spring 2016 CSE 265: System and Network Administration ©2004-2016 Brian D. -
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. -
DMARC: Monitor & Secure Your Email Delivery
Guide DMARC: Monitor & secure your email delivery Chris Nagele Founder of Wildbit postmarkapp.com Read the web version. Do you know every source of email for your domain? Are spammers trying to spoof your email domain for hacking or fraud opportunities? Are you complying with the best email practices to ensure inbox delivery? These are the questions that DMARC answers, giving you full control of email delivery for your company’s domain. At Postmark, email authentication has been extremely important to us from day one. We believe that anyone should be able to easily send emails with proper infrastructure, tools, and email standards without having to pay enterprise prices. DMARC, and our support of it, is a big part of this mission. 2 What is DMARC? DMARC (Domain-based Message Authentication, Reporting & Conformance) is a standard that prevents spammers from using your domain to send email without your permission — also known as spoofing. Spammers can forge the “From” address on messages so the spam appears to come from a user in your domain. A good example of this is PayPal spoofing, where a spammer sends an email to you pretending to be PayPal in an effort to obtain your account information. DMARC ensures these emails get blocked before you even see them in your inbox. In addition, DMARC gives you great visibility and reports into who is sending email on behalf of your domain, ensuring only legitimate email is received. The good news is that DMARC is open and free for anyone to use, allowing you to secure your domain’s emails and gain control of your email delivery. -
Messagelabs Email Security Services Administrator Guide
Email Security Services Administrator Guide For Microsoft Exchange® Environments Licensed Customer Confidential Licensed Customer Confidential Legal Notices Copyright© 1998-2009 Dell MessageOne, Inc. All Rights Reserved. Information in this document is subject to change without notice. All names of companies, organizations, persons, or other entities, and all sample data used in content and examples is fictitious and not meant to represent any real company, organization, person, or actual data. No part of this publication may be reproduced, modified, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise without the prior written permission of Dell MessageOne, Inc. Reproduction prohibitions do not extend to distribution among the employees of licensed customers or for use in activities conducted by Dell MessageOne partners in the course of sales, marketing, training, or support. MessageOne is a registered trademark and “Business Continuity that makes Business Sense,” EMS, SyncManager, RedirectorSink, RedirectorController, RecoveryManager, and OneSwitch are trademarks of Dell MessageOne, Inc. MessageLabs® and the MessageLabs logo are trademarks of MessageLabs Ltd. Research in Motion, RIM, and BlackBerry are trademarks/registered trademarks of Research in Motion Limited. All other trademarks are the property of their respective owners. This product uses certain third-party software. Relevant licensing information is provided in the MESSAGEONE LICENSE file in the installation directory. Dell -
Using Dmarc to Improve Your Email Reputation Zink
USING DMARC TO IMPROVE YOUR EMAIL REPUTATION ZINK USING DMARC TO IMPROVE up with ways to mitigate this problem using two primary technologies. YOUR EMAIL REPUTATION Terry Zink 1.1 Terminology Microsoft, USA In email, people naturally thing that the sender of the message is the one in the From: fi eld – the one that they see in their email Email [email protected] client. For example, suppose that you are a travel enthusiast and you receive the email shown in Figure 3. You received the message ‘from’ [email protected], right? Wrong. ABSTRACT In email, there are two ‘From’ addresses: In 2012, the world of email fi ltering created a new tool to combat 1. The SMTP MAIL FROM, otherwise known as the RFC spam and phishing: DMARC [1, 2]. DMARC, or Domain-based 5321.MailFrom [3]. This is the email address to which the Message Authentication, Reporting & Conformance, is a technology that is designed to prevent spammers from From [email protected] <[email protected]> forging the sender, thus making brands more resistant to Subject Receipt for your Payment to Penguin Magic abuse. However, its most powerful feature is the built-in To Me reporting mechanism that lets brand owners know they are being spoofed. June 10, 2014 08:42:54 PDT DMARC has its upsides, and it is very useful for Transaction ID: 8KAHSL918102341 preventing spoofi ng, but it also has some drawbacks – it will fl ag some legitimate email as spam, and it will Hello Terry Zink, cause some short-term pain. You sent a payment of $427.25 USD to Penguin Magic. -
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. -
98-367: Security Fundamentals
98-367: Security Fundamentals 1. Understand security layers (25–30%) 1.1. Understand core security principles Confidentiality; integrity; availability; how threat and risk impact principles; principle of least privilege; social engineering; attack surface analysis; threat modelling 1.2. Understand physical security Site security; computer security; removable devices and drives; access control; mobile device security; disable Log On Locally; keyloggers 1.3. Understand Internet security Browser security settings; zones; secure websites 1.4. Understand wireless security Advantages and disadvantages of specific security types; keys; service set identifiers (SSIDs); MAC filters 2. Understand operating system security (30–35%) 2.1. Understand user authentication Multifactor authentication; physical and virtual smart cards; Remote Authentication Dial- In User Service (RADIUS); Public Key Infrastructure (PKI); understand the certificate chain; biometrics; Kerberos and time skew; use Run As to perform administrative tasks; password reset procedures 2.2. Understand permissions File system permissions; share permissions; registry; Active Directory; NT file system (NTFS) versus file allocation table (FAT); enable or disable inheritance; behavior when moving or copying files within the same disk or on another disk; multiple groups with different permissions; basic permissions and advanced permissions; take ownership; delegation; inheritance 2.3. Understand password policies Password complexity; account lockout; password length; password history; time -
BOD-18-01 Original Release Date: Applies To: All Federal Executive Branch Departments and Agencies
Secretary U.S. Department of Homeland Security Washington,DC 20528 Homeland Security Binding Operational Directive BOD-18-01 Original Release Date: Applies to: All Federal Executive Branch Departments and Agencies FROM: Elaine C. Duke Acting Secretary OCT 1 6 20t7 CC: Mick Mulvaney Director, Office of Management and Budget SUBJECT: Enhance Email and Web Security A binding operational directive is a compulsory direction to federal, executive branch, departments and agencies for purposes of safeguardingfederal information and information systems. 44 U.S.C. § 3552(b)(l). The Department ofHomeland Security (DHS) develops and oversees the implementation ofbinding operational directivespursuant to the Federal InformationSecurity Modernization Act of2014 ("FISMA"). Id.§ 3553(b)(2). Federal agencies are required to comply with these DHS-developed directives. Id. § 3554(a)(l)(B)(ii). DHS binding operational directivesdo not apply to statutorily defined"National Security Systems" or to certain systems operated by the Department ofDefense orthe Intelligence Community. Id. § 3553(d)-(e). I. Background Federal agency 'cyber hygiene' greatly impacts user security. By implementing specific security standards that have been widely adopted in industry, federal agencies can ensure the integrity and confidentiality of internet-delivered data, minimize spam, and better protect users who might otherwise fall victim to a phishing email that appears to come from a government-owned system. Based on current network scandata and a clear potential forharm, this directive requires actions related to two topics: email security and web security. A. Email Security STARTTLS When enabled by a receiving mail server, STARTTLS signals to a sending mail server that the capability to encrypt an email in transit is present. -
Composition Kills: a Case Study of Email Sender Authentication
Composition Kills: A Case Study of Email Sender Authentication Jianjun Chen, Vern Paxson, and Jian Jiang Component-based software design has been widely adopted as a way to manage complexity and improve reusability. The approach divides complex systems into smaller modules that can be independently created and reused in different systems. One then combines these components together to achieve desired functionality. Modern software systems are commonly built using components made by different developers who work independently. While having wide-ranging benefits, the security research community has recognized that this practice also introduces security concerns. In particular, when faced with crafted adversarial inputs, different components can have inconsistent interpretations when operating on the input in sequence. Attackers can exploit such inconsistencies to bypass security policies and subvert the system’s operation. In this work we provide a case study of such composition issues in the context of email (SMTP) sender authentication. We present 18 attacks for widely used email services to bypass their sender authentication checks by misusing combinations of SPF, DKIM and DMARC, which are crucial defenses against email phishing and spear-phishing attacks. Leveraging these attack techniques, an attacker can impersonate arbitrary senders without breaking email authentication, and even forge DKIM-signed emails with a legitimate site’s signature. Email spoofing, commonly used in phishing attacks, poses a serious threat to both individuals and organiza- tions. Over the past years, a number of attacks used email spoofing or phishing attacks to breach enterprise networks [5] or government officials’ accounts [10]. To address this problem, modern email services and websites employ authentication protocols—SPF, DKIM, and DMARC—to prevent email forgery.