In Computer Networks, A
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
Poster: Introducing Massbrowser: a Censorship Circumvention System Run by the Masses
Poster: Introducing MassBrowser: A Censorship Circumvention System Run by the Masses Milad Nasr∗, Anonymous∗, and Amir Houmansadr University of Massachusetts Amherst fmilad,[email protected] ∗Equal contribution Abstract—We will present a new censorship circumvention sys- side the censorship regions, which relay the Internet traffic tem, currently being developed in our group. The new system of the censored users. This includes systems like Tor, VPNs, is called MassBrowser, and combines several techniques from Psiphon, etc. Unfortunately, such circumvention systems are state-of-the-art censorship studies to design a hard-to-block, easily blocked by the censors by enumerating their limited practical censorship circumvention system. MassBrowser is a set of proxy server IP addresses [14]. (2) Costly to operate: one-hop proxy system where the proxies are volunteer Internet To resist proxy blocking by the censors, recent circumven- users in the free world. The power of MassBrowser comes from tion systems have started to deploy the proxies on shared-IP the large number of volunteer proxies who frequently change platforms such as CDNs, App Engines, and Cloud Storage, their IP addresses as the volunteer users move to different a technique broadly referred to as domain fronting [3]. networks. To get a large number of volunteer proxies, we This mechanism, however, is prohibitively expensive [11] provide the volunteers the control over how their computers to operate for large scales of users. (3) Poor QoS: Proxy- are used by the censored users. Particularly, the volunteer based circumvention systems like Tor and it’s variants suffer users can decide what websites they will proxy for censored from low quality of service (e.g., high latencies and low users, and how much bandwidth they will allocate. -
Threat Modeling and Circumvention of Internet Censorship by David Fifield
Threat modeling and circumvention of Internet censorship By David Fifield A dissertation submitted in partial satisfaction of the requirements for the degree of Doctor of Philosophy in Computer Science in the Graduate Division of the University of California, Berkeley Committee in charge: Professor J.D. Tygar, Chair Professor Deirdre Mulligan Professor Vern Paxson Fall 2017 1 Abstract Threat modeling and circumvention of Internet censorship by David Fifield Doctor of Philosophy in Computer Science University of California, Berkeley Professor J.D. Tygar, Chair Research on Internet censorship is hampered by poor models of censor behavior. Censor models guide the development of circumvention systems, so it is important to get them right. A censor model should be understood not just as a set of capabilities|such as the ability to monitor network traffic—but as a set of priorities constrained by resource limitations. My research addresses the twin themes of modeling and circumvention. With a grounding in empirical research, I build up an abstract model of the circumvention problem and examine how to adapt it to concrete censorship challenges. I describe the results of experiments on censors that probe their strengths and weaknesses; specifically, on the subject of active probing to discover proxy servers, and on delays in their reaction to changes in circumvention. I present two circumvention designs: domain fronting, which derives its resistance to blocking from the censor's reluctance to block other useful services; and Snowflake, based on quickly changing peer-to-peer proxy servers. I hope to change the perception that the circumvention problem is a cat-and-mouse game that affords only incremental and temporary advancements. -
How to Download Torrent Anonymously How to Download Torrent Anonymously
how to download torrent anonymously How to download torrent anonymously. Completing the CAPTCHA proves you are a human and gives you temporary access to the web property. What can I do to prevent this in the future? If you are on a personal connection, like at home, you can run an anti-virus scan on your device to make sure it is not infected with malware. If you are at an office or shared network, you can ask the network administrator to run a scan across the network looking for misconfigured or infected devices. Another way to prevent getting this page in the future is to use Privacy Pass. You may need to download version 2.0 now from the Chrome Web Store. Cloudflare Ray ID: 66b6c3aaaba884c8 • Your IP : 188.246.226.140 • Performance & security by Cloudflare. Download Torrents Anonymously: 6 Safe And Easy Ways. Who doesn’t want to know how to download torrents anonymously? The thing is, in order to download torrents anonymously you don’t need to have a lot of technical know-how. All you need to download torrents anonymously is some grit and a computer with an internet connection. The technology world never remains the same. In fact, new development and discoveries come to the surface of this industry every day. They also come into the attention of online users every year. Moreover, this allows us to do much more than we could do in the past, in faster and easier ways. A highly relevant aspect to mention at this stage is that: Now we can also download torrents anonymously from best torrent sites. -
World-Wide Web Proxies
World-Wide Web Proxies Ari Luotonen, CERN Kevin Altis, Intel April 1994 Abstract 1.0 Introduction A WWW proxy server, proxy for short, provides access to The primary use of proxies is to allow access to the Web the Web for people on closed subnets who can only access from within a firewall (Fig. 1). A proxy is a special HTTP the Internet through a firewall machine. The hypertext [HTTP] server that typically runs on a firewall machine. server developed at CERN, cern_httpd, is capable of run- The proxy waits for a request from inside the firewall, for- ning as a proxy, providing seamless external access to wards the request to the remote server outside the firewall, HTTP, Gopher, WAIS and FTP. reads the response and then sends it back to the client. cern_httpd has had gateway features for a long time, but In the usual case, the same proxy is used by all the clients only this spring they were extended to support all the within a given subnet. This makes it possible for the proxy methods in the HTTP protocol used by WWW clients. Cli- to do efficient caching of documents that are requested by ents don’t lose any functionality by going through a proxy, a number of clients. except special processing they may have done for non- native Web protocols such as Gopher and FTP. The ability to cache documents also makes proxies attrac- tive to those not inside a firewall. Setting up a proxy server A brand new feature is caching performed by the proxy, is easy, and the most popular Web client programs already resulting in shorter response times after the first document have proxy support built in. -
Technical and Legal Overview of the Tor Anonymity Network
Emin Çalışkan, Tomáš Minárik, Anna-Maria Osula Technical and Legal Overview of the Tor Anonymity Network Tallinn 2015 This publication is a product of the NATO Cooperative Cyber Defence Centre of Excellence (the Centre). It does not necessarily reflect the policy or the opinion of the Centre or NATO. The Centre may not be held responsible for any loss or harm arising from the use of information contained in this publication and is not responsible for the content of the external sources, including external websites referenced in this publication. Digital or hard copies of this publication may be produced for internal use within NATO and for personal or educational use when for non- profit and non-commercial purpose, provided that copies bear a full citation. www.ccdcoe.org [email protected] 1 Technical and Legal Overview of the Tor Anonymity Network 1. Introduction .................................................................................................................................... 3 2. Tor and Internet Filtering Circumvention ....................................................................................... 4 2.1. Technical Methods .................................................................................................................. 4 2.1.1. Proxy ................................................................................................................................ 4 2.1.2. Tunnelling/Virtual Private Networks ............................................................................... 5 -
Who Wrote Sobig? Copyright 2003-2004 Authors Page 1 of 48
Who Wrote Sobig? Copyright 2003-2004 Authors Page 1 of 48 Who Wrote Sobig? Version 1.0: 19-August-2003. Version 1.1: 25-August-2003. Version 1.2: 19-November-2003. Version 1.3: 17-July-2004. This sanitized variation for public release. Scheduled for release: 1-November-2004. This document is Copyright 2003-2004 by the authors. The PGP key included within this document identifies the authors. Who Wrote Sobig? Copyright 2003-2004 Authors Page 2 of 48 Table of Contents Table of Contents................................................................................................................................................... 2 1 About This Document..................................................................................................................................... 3 2 Overview........................................................................................................................................................ 5 3 Spam and Virus Release History..................................................................................................................... 6 3.1 Identifying Tools .................................................................................................................................... 6 3.2 Identifying Individuals and Specific Groups ............................................................................................ 6 3.3 Identifying Open Proxies and Usage........................................................................................................ 8 3.4 -
Spam Solutions White Paper
Spam Solutions White Paper Presented by: Net Sense Net Sense – IT Consulting 1 Phone: 919.870.8889 www.netsense.info Toll Free: 800.642.8360 Spam Solutions White Paper ...........................................................................................1 Spam Problem Overview.............................................................................................3 What Is Spam?.........................................................................................................3 Who Sends Spam?...................................................................................................3 How Is Spam Sent?..................................................................................................4 How Is Spam Identified? .........................................................................................4 What Problems Does Spam Cause?..........................................................................5 Legal Considerations For Business ..........................................................................5 Illegal or offensive content:..................................................................................6 Anti-Spam Laws......................................................................................................7 CAN-SPAM Act......................................................................................................7 How To Avoid Becoming A Spam Magnet..............................................................7 Tips for users:......................................................................................................7 -
The Measured Access Characteristics of World-Wide-Web Client Proxy Caches
The following paper was originally published in the Proceedings of the USENIX Symposium on Internet Technologies and Systems Monterey, California, December 1997 The Measured Access Characteristics of World-Wide-Web Client Proxy Caches Bradley M. Duska, David Marwood, and Michael J. Feeley University of British Columbia For more information about USENIX Association contact: 1. Phone: 510 528-8649 2. FAX: 510 548-5738 3. Email: [email protected] 4. WWW URL:http://www.usenix.org/ The Measured Access Characteristics of World-Wide-Web Client Proxy Caches Bradley M. Duska, David Marwood, and Michael J. Feeley Department of Computer Science University of British Columbia g fbduska,marwood,feeley @cs.ubc.ca Abstract three fronts. The ®rst is to scale Web servers to handle the increasing demands being placed on them. The sec- The growing popularity of the World Wide Web is plac- ond is to ensure that the Internet itself will scale by con- ing tremendous demands on the Internet. A key strategy tinuing to increase its capacity and by deploying new net- for scaling the Internet to meet these increasing demands work technologies. The third is to focus on the clients: is to cache data near clients and thus improve access la- Web browsers and a hierarchy of proxy servers to which tency and reduce network and server load. Unfortunately, they may be connected. research in this area has been hampered by a poor un- Client-side solutions such as caching and prefetching derstanding of the locality and sharing characteristics of are attractive because they improve the performance of Web-client accesses. -
Botnets, Zombies, and Irc Security
Botnets 1 BOTNETS, ZOMBIES, AND IRC SECURITY Investigating Botnets, Zombies, and IRC Security Seth Thigpen East Carolina University Botnets 2 Abstract The Internet has many aspects that make it ideal for communication and commerce. It makes selling products and services possible without the need for the consumer to set foot outside his door. It allows people from opposite ends of the earth to collaborate on research, product development, and casual conversation. Internet relay chat (IRC) has made it possible for ordinary people to meet and exchange ideas. It also, however, continues to aid in the spread of malicious activity through botnets, zombies, and Trojans. Hackers have used IRC to engage in identity theft, sending spam, and controlling compromised computers. Through the use of carefully engineered scripts and programs, hackers can use IRC as a centralized location to launch DDoS attacks and infect computers with robots to effectively take advantage of unsuspecting targets. Hackers are using zombie armies for their personal gain. One can even purchase these armies via the Internet black market. Thwarting these attacks and promoting security awareness begins with understanding exactly what botnets and zombies are and how to tighten security in IRC clients. Botnets 3 Investigating Botnets, Zombies, and IRC Security Introduction The Internet has become a vast, complex conduit of information exchange. Many different tools exist that enable Internet users to communicate effectively and efficiently. Some of these tools have been developed in such a way that allows hackers with malicious intent to take advantage of other Internet users. Hackers have continued to create tools to aid them in their endeavors. -
What Is SOCKS?
Version 2.0 What is SOCKS? An explanation of the SOCKS protocol and application proxy gateway systems B. Scott Wilson, CISSP IBM Global Services, Network Services What is SOCKS? ! SOCKS is a generic proxy protocol for TCP/IP-based networking applications. ! The SOCKS protocol provides a flexible framework for developing secure communications by easily integrating other security technologies. 2 How does it Work? ! When an application client needs to connect to an application server, the client machine connects to a SOCKS proxy server. The proxy server connects to the application server on behalf of the client, and relays data between the client and the application server. ! For the application server, the proxy server is the client. 3 The SOCKS Protocol ! SOCKS version 5 is an IETF approved standard protocol implementation (RFC 1928). ! SOCKS includes two components, the SOCKS server and the SOCKS client. The SOCKS server is implemented at the application layer, while the SOCKS client is implemented between the application and transport layers (see next slide). ! The basic purpose of the protocol is to enable hosts on one side of a SOCKS server to gain access to hosts on the other side of a SOCKS Server, without requiring direct “IP-reachability”. 4 SOCKS and the OSI Layer Model 5 Functions of SOCKS ! The SOCKS protocol performs four functions: " Making connection requests " Setting up proxy circuits " Relaying application data " Performing user authentication (optional) 6 Features of SOCKS ! Transparent network access across multiple proxy servers ! Easy deployment of authentication and encryption methods ! Rapid deployment of new network applications ! Simple network security policy management 7 Benefits of SOCKS ! A single communication protocol authenticates users and establishes the communication channel ! SOCKS is application independent ! Can be used with either UDP or TCP based protocols; even supports redirection of ICMP! ! Bi-directional support and intrinsic NAT, for added security and anti-spoofing. -
Hypertext Transfer Protocol
Hypertext Transfer Protocol Ing. Pierluigi Gallo HTTP Hypertext Transfer Protocol used in the WWW protocol used for communication between web browsers and web servers client-server paradigm TCP port 80 RFC 1945 Ing. Pierluigi Gallo Introduction to HTTP 80% of Internet flows are HTTP connections Early protocol is HTTP 0.9 read only Today we use HTTP 1.0 read, input, delete, ... New version: HTTP 1.1 performance optimizations Ing. Pierluigi Gallo HTTP Overview Client (browser) sends HTTP request to server Request specifies affected URL Request specifies desired operation Server performs operation on URL Server sends response Request and reply headers are in pure text Ing. Pierluigi Gallo Static Content and HTML Most static web content is written in HTML HTML allows Text formatting commands Embedded objects Links to other objects Server need not understand or interpret HTML Ing. Pierluigi Gallo URI,URN,URL RFC 3305 Uniform Resource Identifier Identifies a resource Uniform Resource Name The name of the resource with in a namespace like a person’s name Uniform Resource Locator How to find the resource, a URI that says how to find the resource like a person street address URI concept is more general than its use in web pages (XML, …) Ing. Pierluigi Gallo HTTP - URLs URL Uniform Resource Locator protocol (http, ftp, news) host name (name.domain name) port (80, 8080, …) directory path to the resource resource name absolute relative http://www.tti.unipa.it/~pg/pg/Teaching.html http://xxx.myplace.com:80/cgi-bin/t.exe Ing. Pierluigi Gallo URI examples http://example.org/absolute/URI/with/absolute/ path/to/resource.txt ftp://example.org/resource.txt urn:issn:1535-3613 /relative/URI/with/absolute/path/to/resource.txt relative/path/to/resource.txt ../../../resource.txt ./resource.txt#frag01 Ing. -
Firewall and Proxy Server HOWTO Firewall and Proxy Server HOWTO
Firewall and Proxy Server HOWTO Firewall and Proxy Server HOWTO Table of Contents Firewall and Proxy Server HOWTO................................................................................................................1 Mark Grennan, mark@grennan.com.......................................................................................................1 1.Introduction...........................................................................................................................................1 2.Understanding Firewalls.......................................................................................................................1 3.Firewall Architecture ...........................................................................................................................1 4.Setting up the Linux Filtering Firewall ................................................................................................1 5.Software requirements..........................................................................................................................1 6.Preparing the Linux system..................................................................................................................2 7.IP filtering setup (IPFWADM).............................................................................................................2 8.IP filtering setup (IPCHAINS)..............................................................................................................2 9.Making it easy−er.................................................................................................................................2