Peer-to-peer (P2P) file-sharing allows users to share files online through an informal network of computers running the same software. File-sharing can give you access to a wealth of information, but it also has a number of risks. You could download copyright-protected material, pornography, or viruses without meaning to. Or you could mistakenly allow other people to copy files you don’t mean to share.

 

Peer-to-peer architecture is a type of network in which each workstation has equivalent capabilities and responsibilities. (Techniques will continue to be used to lure users to download what appears to be music and other media files.)

P2P is often used as as a term to describe one user linking with another user to transfer information and files through the use of a common P2P client to download MP3s, videos, images, games and other software. P2P networks can also mean Grid Computing or Instant messaging.   Every day, millions of computer users share files online. Whether it is music, games, or software, file-sharing can give people access to a wealth of information. You simply download special software that connects your computer to an informal network of other computers running the same software. Millions of users could be connected to each other through this software at one time. The software often is free and easily accessible.

 

How Peer-to-peer File-sharing Clients Work
Once you have downloaded and installed a P2P client, if you are connected to the Internet you can launch the utility and you are then logged into a central indexing server. This central server indexes all users who are currently online connected to the server. This server does not host any files for downloading. The P2P client will contain an area where you can search for a specific file. The utility queries the index server to find other connected users with the file you are looking for. When a match is found the central server will tell you where to find the requested file. You can then choose a result from the search query and your utility when then attempt to establish a connection with the computer hosting the file you have requested. If a successful connection is made, you will begin downloading the file. Once the file download is complete the connection will be broken.

 

Here is a list of some of the more popular file-sharing programs. You may want to look to see if any of these are installed on your computer.

 

Windows Programs		Mac Programs
Aimster Audio Galaxy Bearshare Gnotella Gnucleus Grokster	iMesh KaZaa Limewire Morpheus SwapNut WinMX	Aimster Limewire Mactella

 

A second model of P2P clients works in the same way but without a central indexing server. In this scenario the P2P software simply seeks out other Internet users using the same program and informs them of your presence online, building a large network of computers as more users install and use the software.

 

P2P File-Sharing: Evaluate the Risks

File-sharing can have a number of risks. For example, when you are connected to file-sharing programs, you may unknowingly allow others to copy private files you never intended to share. You may download material that is protected by the copyright laws and find yourself mired in legal issues. You may download a virus or facilitate a security breach. Or you may unwittingly download pornography labeled as something else.

 

To secure the personal information stored on your computer, we suggest that you:

Set up the file-sharing software very carefully. If you don’t check the proper settings when you install the software, you could open access not just to the files you intend to share, but also to other information on your hard drive, like your tax returns, email messages, medical records, photos, or other personal documents.

 

Be aware of spyware. Some file-sharing programs install other software known as spyware. Spyware monitors a user’s browsing habits and then sends that data to third parties. Sometimes the user gets ads based on the information that the spyware has collected and disseminated. Spyware can be difficult to detect and remove. Before you use any file-sharing program, you may want to buy software that can prevent the downloading of spyware or help detect it on your hard drive.

 

Close your connection. In some instances, closing the file-sharing program window does not actually close your connection to the network. That allows file-sharing to continue and could increase your security risk. If you have a high-speed or “broadband” connection to the Internet, you stay connected to the Internet unless you turn off the computer or disconnect your Internet service. These “always on” connections may allow others to copy your shared files at any time. What’s more, some file-sharing programs automatically open every time you turn on your computer. As a preventive measure, you may want to adjust the file-sharing program’s controls to prevent the file-sharing program from automatically opening.

 

Use an effective anti-virus program and update it regularly. Files you download could be mislabeled, hiding a virus or other unwanted content. Use anti-virus software to protect your computer from viruses you might pick up from other users through the file-sharing program. Not all anti-virus programs block files downloaded through file-sharing, so check your program’s capabilities and settings. In addition, avoid downloading files with extensions like .exe, .scr, .lnk, .bat, .vbs, .dll, .bin, and .cmd.

 

Talk with your family about file-sharing. Parents may not be aware that their children have downloaded file-sharing software on the family computer and that they may have exchanged games, videos, music, pornography, or other material that may be inappropriate for them. Also, because other peoples’ files sometimes are mislabeled, kids unintentionally may download these files. In addition, kids may not understand the security and other risks involved with file-sharing and may install the software incorrectly, giving anyone on the Internet access to the family’s private computer files.

 

Types of P2P Networks

 

Collaborative Computing
Also referred to as distributed computing, it combines the idle or unused CPU processing power and/or free disk space of many computers in the network. Collaborative computing is most popular with science and biotech organizations where intense computer processing is required. Examples of distributed computing can be found at GRID.ORG where United Devices is hosting virtual screening for cancer research on the Grid MP platform. This project has evolved into the largest computational chemistry project in history. United Devices has harnessed the power of more than 2,000,000 PCs around the world to generate more than 100 teraflops of power. Most distributed computing networks are created by users volunteering their unused computing resources to contribute to public interest research projects.

 

Instant Messaging
One very common form of P2P networking is Instant Messaging (IM) where software applications, such as MSN Messenger or AOL Instant Messenger, for example, allow users to chat via text messages in real-time. While most vendors offer a free version of their IM software others have begun to focus on enterprise versions of IM software as business and corporations have moved towards implementing IM as a standard communications tool for business.

 

Affinity Communities
Affinity communities is the group of P2P networks that is based around file-sharing and became widely known and talked about due to the public legal issues surrounding the direct file sharing group, Napster. Affinity Communities are based on users collaborating and searching other user's computers for information and files.

 

P2P at Work

P2P is not only popular with home users but many small business have come to rely on this cost-effective solution for sharing files with co-workers and clients. P2P promotes the ease of working together when you're not physically located in the same office. In just seconds updated files and data can be shared with peers and confidential files can be blocked for security. Additionally, companies can also block access to Internet music and video files to assist in maintaining a work-oriented P2P network. Not only does this keep the company free and clear from legal issues regarding music downloading and sharing but it also keeps the corporate bandwidth usage down.

 

P2P Security Concerns

One major concern of using P2P architecture in the workplace is, of course, network security. Security concerns stem from the architecture itself. Today we find most blocking and routing handles by a specific server within network, but the P2P architecture has no single fixed server responsible for routing and requests. The first step in securing your P2P network is to adopt a strict usage policy within the workplace. In securing your network against attacks and viruses there are two main strategies where focus is on controlling the network access or the focus is put on controlling the files. A protocol-based approach is where system administrators use a software or hardware solution to watch for and block intrusive network traffic being received through the P2P clients. A second method of protection is a software solution which would provide file surveillance to actively search for files based on their type, their name, their signature or even their content.

 

Overriding Page Content
Several methods exist for Phishers to override displayed content. One of the most popular methods of inserting fake content within a page is to use the DHTML function - DIV. The DIV function allows an attacker to place content into a ?virtual container? that, when given an absolute position and size through the STYLE method, can be positioned to hide or replace (by ?sitting on top?) underlying content. This malicious content may be delivered as a very long URL or by referencing a stored script.  This method allows an attacker to build a complete page (including graphics and auxiliary scripting code elements) on top of the real page.

 

Graphical Substitution
While it is possible to overwrite page content easily through multiple methods, one problem facing Phishers is that of browser specific visual clues to the source of an attack. These clues include the URL presented within the browsers URL field, the secure padlock representing an HTTPS encrypted connection, and the Zone of the page source.

 

A common method used to overcome these visual clues is through the use of browser scripting languages (such as JavaScript, VBScript and Java) to position specially created graphics over these key areas with fake information.

 

While the Phisher must use graphics that are appropriate to the manufacturer of the browser software, it is a trivial exercise for the attackers fake web site to determine the browser type and exact version through simple code queries. Therefore the attacker may prepare images for a range of common browsers and code their page in such a way that the appropriate images are always used.

It is important to note that Phishing attacks in the past have combined graphical substitution
with additional scripting code to fake other browser functionality.

 

Examples include:

 

Implementing "right-click" functionality and menu access,

Presenting false popup messages just as the real browser or web application would,

Displaying fake SSL certificate details when reviewing page properties or security settings -  through the use of images.