Different Protocols Used in Email
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SMTP (Simple Mail Transfer Protocol)
P1: JsY JWBS001A-60.tex WL041/Bidgoli WL041-Bidgoli.cls May 12, 2005 3:27 Char Count= 0 SMTP (Simple Mail Transfer Protocol) Vladimir V. Riabov, Rivier College Introduction 1 SMTP Security Issues 12 SMTP Fundamentals 1 SMTP Vulnerabilities 12 SMTP Model and Protocol 2 SMTP Server Buffer Overflow Vulnerability 15 User Agent 4 Mail Relaying SMTP Vulnerability 15 Sending e-Mail 4 Mail Relaying SMTP Vulnerability in Microsoft Mail Header Format 4 Windows 2000 15 Receiving e-Mail 4 Encapsulated SMTP Address Vulnerability 15 The SMTP Destination Address 4 Malformed Request Denial of Service 16 Delayed Delivery 4 Extended Verb Request Handling Flaw 16 Aliases 5 Reverse DNS Response Buffer Overflow 16 Mail Transfer Agent 5 Firewall SMTP Filtering Vulnerability 16 SMTP Mail Transaction Flow 5 Spoofing 16 SMTP Commands 6 Bounce Attack 16 Mail Service Types 6 Restricting Access to an Outgoing Mail SMTP Service Extensions 8 Server 17 SMTP Responses 8 Mail Encryption 17 SMTP Server 8 Bastille Hardening System 17 On-Demand Mail Relay 8 POP and IMAP Vulnerabilities 17 Multipurpose Internet Mail Extensions Standards, Organizations, and (MIME) 8 Associations 18 MIME-Version 10 Internet Assigned Numbers Authority 18 Content-Type 10 Internet Engineering Task Force Working Content-Transfer-Encoding 10 Groups 18 Content-Id 11 Internet Mail Consortium 18 Content-Description 11 Mitre Corporation 18 Security Scheme for MIME 11 Conclusion 18 Mail Transmission Types 11 Glossary 18 Mail Access Modes 11 Cross References 19 Mail Access Protocols 11 References 19 POP3 11 Further Reading 22 IMAP4 12 INTRODUCTION and IMAP4), SMTP software, vulnerability and security issues, standards, associations, and organizations. -
SMTP Protocol
CS 280 Lecture 4: Application Layer, Email, DNS, P2P John Magee 21 September 2016 Most slides adapted from Kurose and Ross, Computer Networking 7/e Source material copyright 1996-2016 1 J.F Kurose and K.W. Ross Chapter 2: outline Last Class: 2.1 principles of network Next Class: applications 2.6 video streaming and 2.2 Web and HTTP content distribution networks Today: 2.7 socket programming with UDP and TCP 2.3 electronic mail • SMTP, POP3, IMAP 2.4 DNS 2.5 P2P applications Application Layer 2-2 outgoing Electronic mail message queue user mailbox Three major components: user agent . user agents . mail servers mail user server . simple mail transfer agent protocol: SMTP SMTP mail user server agent User Agent SMTP . a.k.a. “mail reader” SMTP user agent . composing, editing, reading mail server mail messages user . e.g., Outlook, Thunderbird, agent iPhone mail client user . outgoing, incoming agent messages stored on server Application Layer 2-3 Electronic mail: mail servers mail servers: user agent . mailbox contains incoming messages for user mail user server . message queue of outgoing agent (to be sent) mail messages SMTP mail user . SMTP protocol between server agent mail servers to send email SMTP messages SMTP user agent • client: sending mail mail server server • “server”: receiving mail user server agent user agent Application Layer 2-4 Electronic Mail: SMTP [RFC 2821] . uses TCP to reliably transfer email message from client to server, port 25 . direct transfer: sending server to receiving server . three phases of transfer • handshaking (greeting) • transfer of messages • closure . command/response interaction (like HTTP) • commands: ASCII text • response: status code and phrase . -
Statement from Directtrust Regarding the EFAIL Vulnerability
Statement from DirectTrust regarding the EFAIL Vulnerability Summary EFAIL is a set of attacks used to exploit vulnerabilities in email clients that decrypt and display PGP and S/MIME encrypted messages by coercing them into sending the decrypted text of the emails to an attacker. Properly implemented, Direct is NOT vulnerable. However, we recommend that if you are exchanging with anyone outside of the DirectTrust Network, you will want to understand at a reasonable depth how their implementation protects against EFAIL. How does EFAIL work? EFAIL consists of two different attack scenarios that create “backchannels” to send the decrypted text to an attacker. Both require an attacker to first obtain the encrypted message. 1. The attacker “wraps” the encrypted body with carefully crafted markup that can result in an email client decrypting the message and sending the decrypted body to the attacker. 2. The attacker manipulates the encrypted body of the message using well known S/MIME weaknesses that produce a message that can send the decrypted body to the attacker once rendered in the email client. Although the attacks are different, the end result is the same: a vulnerable email client sends the decrypted text to the attacker. How is this relevant to Direct? Direct uses S/MIME to encrypt messages, so in theory every Direct message could be vulnerable to this attack. However, Direct, when implemented correctly, is NOT vulnerable. The vulnerability is only applicable if decryption and rendering of the message are done in certain email clients like Thunderbird, iOS, Apple Mail, and some versions of Outlook. -
Understanding Post Office Protocol (POP3)
Understanding Post Office Protocol (POP3) Author: Conrad Chung, 2BrightSparks Introduction Most Internet users with email accounts would have used some form of “client” software (Outlook, Thunderbird etc.) to access and manage their email at one point or another. To retrieve emails, these email clients may require the configuration of Post Office Protocol (or POP3) before messages can be downloaded from the server. This article will help readers understand what POP3 is and how it works. What is Post Office Protocol? The Post Office Protocol (POP3) is an Internet standard protocol used by local email software clients to retrieve emails from a remote mail server over a TCP/IP connection. Since the first version was created in 1984, the Post Office Protocol (currently at Version 3) has since became one of the most popular protocols and is used by virtually every email client to date. Its popularity lies in the protocol’s simplicity to configure, operate and maintain. Email servers hosted by Internet service providers also use POP3 to receive and hold emails intended for their subscribers. Periodically, these subscribers will use email client software to check their mailbox on the remote server and download any emails addressed to them. Once the email client has downloaded the emails, they are usually deleted from the server, although some email clients allow users to specify that mails be copied or saved on the server for a period of time. Email clients generally use the well-known TCP port 110 to connect to a POP3 server. If encrypted communication is supported on the POP3 server, users can optionally choose to connect either by using the STLS command after the protocol initiation stage or by using POP3S, which can use the Transport Layer Security (TLS) or Secure Sockets Layer (SSL) on TCP port 995 to connect to the server. -
Getting Started with Eudora 5.1 for Windows 95/98/ME/NT/2000 Author Teresa Sakata
WIN9X003 July 2003 Getting Started with Eudora 5.1 For Windows 95/98/ME/NT/2000 Author Teresa Sakata Introduction ..............................................................................................................................................................1 POP and IMAP Servers ............................................................................................................................................2 Requirements ............................................................................................................................................................2 Changes From Version 4.3.x ....................................................................................................................................3 Issues ........................................................................................................................................................................3 Where do I get Eudora? ............................................................................................................................................4 Getting Started..........................................................................................................................................................4 Installation ................................................................................................................................................................4 Configuring Eudora ..................................................................................................................................................5 -
What Is the Difference Between Email Protocols
What Is The Difference Between Email Protocols Interactions between email servers and users are governed by email protocols. The most common incoming email protocols are POP, and IMAP. Most email applications/programs support one or more of these. This article is to help users understand and choose which protocol should be selected for each user’s situation. Outgoing Incoming POP (Post Office Protocol): IMAP (Internet Message Access Protocol): SSL (Secure Socket Layer): Differences Between POP and IMAP Backups / Email Loss Outgoing SMTP (Simple Mail Transfer Protocol) is the protocol used in sending (outgoing) emails. SMTP is the protocol always used for sending (outgoing) emails. Incoming POP (Post Office Protocol) and IMAP (Internet Message Access Protocol) are two different protocols that do the same thing differently. They are both used in receiving emails from a mail server and can both are available for standard and secure (?) connections. POP (Post Office Protocol): POP is an email accessing protocol used to download emails from a mail server. Applications like Outlook and Outlook Express using POP will download all emails from the server to the user’s computer, and then delete them on the server. Generally POP server uses port 110 to listen to the POP requests or securely using SSL (Secure Socket Layer) (?) POP uses port number 995. The POP protocol assumes that there is only one client/computer that will be connecting to the mailbox. Even though there is an option in most mail applications to leave the copies of the emails in the server, it is not generally used due to various reasons. -
Ii Jacobs Rp316
!II JACOBS RP316 RACIBORZ FLOOD RESERVOIR Public Disclosure Authorized Resettlement Action Plan Public Disclosure Authorized DRAFT Public Disclosure Authorized Public Disclosure Authorized March 2005 JACOBS Document control sheet Form IP180/B Client: PCU Project: Odra Flood Mitigation Job No: J24201A Title: Draft Resettlement Action Plan Prepared by Reviewed by Approved by ORIGINAL0 NAME NAME NAME P Devitt L J S Attewill see list of authors H Fiedler-Krukowicz J Loch | DATfE SIGNATURE SIGNATURE SIGNATURE REVISION NAME NAME NAME DATE SIGNATURE SIGNATURE SIGNATURE REVISION NAME NAME NAME DATE SIGNATURE SIGNATURE SIGNATURE REVISION NAME NAME NAME DATE SIGNATURE SIGNATURE SIGNATURE This report, and infonnabon or advice which it contains, is provided by JacobsGIBB Ltd solely for internal use and reliance by its Cient in performance of JacobsGIBB Ltd's duties and liabilities under its contract with the Client Any advice, opinions, or recomrnendatons within this report should be read and retied upon only in the context of the report as a whole. The advice and opinions in this report are based upon the information nmadeavailable to JacobsGIBB Ltd at the date of this report and on current UK standards, codes, technology and constnuction practices as at the date of this report. Folloving final delvery of this report to the Client, JacobsGIBB Ltd will have no further obligations or duty to advise She Client on any mafters, including developrrient affecting the information or advice provided in ths report This report has been prepared by JacobsGIBB Ltd in their professional capaaty as Consuhing Engineers The contents of the report do not, in any way, purport to include any mranner of legal advice or opinion This report is prepared in accordance wrth the terms and conditions of JacobsGIBB Ltd's contract with the Client. -
HTTP Cookie - Wikipedia, the Free Encyclopedia 14/05/2014
HTTP cookie - Wikipedia, the free encyclopedia 14/05/2014 Create account Log in Article Talk Read Edit View history Search HTTP cookie From Wikipedia, the free encyclopedia Navigation A cookie, also known as an HTTP cookie, web cookie, or browser HTTP Main page cookie, is a small piece of data sent from a website and stored in a Persistence · Compression · HTTPS · Contents user's web browser while the user is browsing that website. Every time Request methods Featured content the user loads the website, the browser sends the cookie back to the OPTIONS · GET · HEAD · POST · PUT · Current events server to notify the website of the user's previous activity.[1] Cookies DELETE · TRACE · CONNECT · PATCH · Random article Donate to Wikipedia were designed to be a reliable mechanism for websites to remember Header fields Wikimedia Shop stateful information (such as items in a shopping cart) or to record the Cookie · ETag · Location · HTTP referer · DNT user's browsing activity (including clicking particular buttons, logging in, · X-Forwarded-For · Interaction or recording which pages were visited by the user as far back as months Status codes or years ago). 301 Moved Permanently · 302 Found · Help 303 See Other · 403 Forbidden · About Wikipedia Although cookies cannot carry viruses, and cannot install malware on 404 Not Found · [2] Community portal the host computer, tracking cookies and especially third-party v · t · e · Recent changes tracking cookies are commonly used as ways to compile long-term Contact page records of individuals' browsing histories—a potential privacy concern that prompted European[3] and U.S. -
Migrationsleitfaden
Migrationsleitfaden Leitfaden für die Migration der Basissoftwarekomponenten auf Server- und Arbeitsplatz-Systemen Version 1.0 – Juli 2003 Schriftenreihe der KBSt ISSN 0179-7263 Band 57 Juli 2003 Schriftenreihe der KBSt Band 57 ISSN 0179 - 7263 Nachdruck, auch auszugsweise, ist genehmigungspflichtig Dieser Band wurde erstellt von der KBSt im Bundesministeri- um des Innern in Zusammenarbeit mit dem Bundesamt für Sicherheit in der Informationstechnik (BSI), dem Bundesver- waltungsamt (BVA) und der C_sar Consulting, solutions and results AG Redaktion: C_sar AG, Berlin Interessenten erhalten die derzeit lieferbaren Veröffentlichungen der KBSt und weiterführende Informationen zu den Dokumenten bei Bundesministerium des Innern Referat IT 2 (KBSt) 11014 Berlin Tel.: +49 (0) 1888 681 - 2312 Fax.: +49 (0) 1888 681 - 523121 Homepage der KBSt: http://www.kbst.bund.de 1Frau Monika Pfeiffer (mailto: [email protected]) Migrationsleitfaden Leitfaden für die Migration der Basissoftwarekomponenten auf Server- und Arbeitsplatz-Systemen Version 1.0 Juli 2003 Herausgegeben vom Bundesministerium des Innern INHALTSVERZEICHNIS 1 Einleitung ........................................................................ 8 1.1 Über das Vorhaben 8 1.2 Über diesen Leitfaden 9 1.3 Hinweise zur Benutzung des Leitfadens 10 1.4 Hinweise an die Entscheider 12 1.4.1 Grundsätzliche Empfehlungen 12 1.4.2 Fortführende und ablösende Migration 13 1.4.3 Migrationswege 14 1.4.4 Vergleichbarkeit von Alternativen 14 1.4.5 Künftige Schwerpunte 15 1.4.6 Wirtschaftlichkeit 16 -
[Hal-00744922, V1] Improving Content Availability in the I2P Anonymous
Improving Content Availability in the I2P Anonymous File-Sharing Environment Juan Pablo Timpanaro, Isabelle Chrisment*, Olivier Festor INRIA Nancy-Grand Est, France *LORIA - ESIAL, Universit´ede Lorraine Email: fjuanpablo.timpanaro, [email protected] Email: [email protected] Abstract. Anonymous communication has gained more and more inter- est from Internet users as privacy and anonymity problems have emerged. Dedicated anonymous networks such as Freenet and I2P allow anony- mous file-sharing among users. However, one major problem with anony- mous file-sharing networks is that the available content is highly reduced, mostly with outdated files, and non-anonymous networks, such as the BitTorrent network, are still the major source of content: we show that in a 30-days period, 21648 new torrents were introduced in the BitTor- rent community, whilst only 236 were introduced in the anonymous I2P network, for four different categories of content. Therefore, how can a user of these anonymous networks access this varied and non-anonymous content without compromising its anonymity? In this paper, we improve content availability in an anonymous environment by proposing the first internetwork model allowing anonymous users to access and share content in large public communities while remaining anonymous. We show that our approach can efficiently interconnect I2P users and public BitTorrent swarms without affecting their anonymity nor their performance. Our model is fully implemented and freely usable. 1 Introduction Peer-to-peer file-sharing has always been one of the major sources of the Internet hal-00744922, version 1 - 24 Oct 2012 traffic, since its early beginnings in 2000. It has been moving from semi-central approaches (eDonkey2000, for example), to semi-decentralized approaches (Kazaa, for instance) to fully decentralized file-sharing architectures (like the KAD net- work). -
Security with SSH.Pdf
Security with SSH Network Startup Resource Center http://www.nsrc.org/ These materials are licensed under the Creative Commons Attribution-NonCommercial 4.0 International license (http://creativecommons.org/licenses/by-nc/4.0/) Topics • What is SSH • Where to get SSH • How to enable and configure SSH • Where to get SSH clients for Windows • Host keys: authentication of server to client • Issues to do with changing of the host key • Password authentication of client to server • Cryptographic authentication client to server • hostkey exchange, scp, and sftp labs What is SSH? From Wikipedia: Secure Shell (SSH) is a cryptographic network protocol for secure data communication, remote command-line login, remote command execution, and other secure network services between two networked computers that connects, via a secure channel over an insecure network, a server and a client (running SSH server and SSH client programs, respectively). i.e., ssh gives you a secure command line interface on remote machines… Topics • Where SSH applies directly to dealing with these two areas of security: - Confidentiality - Keeping our data safe from prying eyes • Authentication and Authorization - Is this person who they claim to be? - With keys alternative method to passwords Where to get SSH • First see if SSH is installed on your system and what version. Easiest way is: $ ssh ±V • Commonly used SSH in Linux and FreeBSD is OpenSSH. You can find the home page here: http://www.openssh.org/ • You can install OpenSSH via packages on Linux and FreeBSD. Ubuntu 12.04.3 LTS currently installs version 5.9p1 of OpenSSH. Obtain SSH Client for Windows There are several free, shareware, and commercial ssh clients for Windows. -
GNU Guix Cookbook Tutorials and Examples for Using the GNU Guix Functional Package Manager
GNU Guix Cookbook Tutorials and examples for using the GNU Guix Functional Package Manager The GNU Guix Developers Copyright c 2019 Ricardo Wurmus Copyright c 2019 Efraim Flashner Copyright c 2019 Pierre Neidhardt Copyright c 2020 Oleg Pykhalov Copyright c 2020 Matthew Brooks Copyright c 2020 Marcin Karpezo Copyright c 2020 Brice Waegeneire Copyright c 2020 Andr´eBatista Copyright c 2020 Christine Lemmer-Webber Copyright c 2021 Joshua Branson Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled \GNU Free Documentation License". i Table of Contents GNU Guix Cookbook ::::::::::::::::::::::::::::::: 1 1 Scheme tutorials ::::::::::::::::::::::::::::::::: 2 1.1 A Scheme Crash Course :::::::::::::::::::::::::::::::::::::::: 2 2 Packaging :::::::::::::::::::::::::::::::::::::::: 5 2.1 Packaging Tutorial:::::::::::::::::::::::::::::::::::::::::::::: 5 2.1.1 A \Hello World" package :::::::::::::::::::::::::::::::::: 5 2.1.2 Setup:::::::::::::::::::::::::::::::::::::::::::::::::::::: 8 2.1.2.1 Local file ::::::::::::::::::::::::::::::::::::::::::::: 8 2.1.2.2 `GUIX_PACKAGE_PATH' ::::::::::::::::::::::::::::::::: 9 2.1.2.3 Guix channels ::::::::::::::::::::::::::::::::::::::: 10 2.1.2.4 Direct checkout hacking:::::::::::::::::::::::::::::: 10 2.1.3 Extended example ::::::::::::::::::::::::::::::::::::::::