24-04-2012, 04:12 PM
SECURITY
internetsecurity.doc (Size: 25 KB / Downloads: 27)
INTRODUCTION
If there was ever a need to give your desktop security a boost, it is now Take, for example, the e-mail worms Despite all sorts of network protection, they still manage to get inside and do their deeds Navidad exe, kak hta,loveletter etc the list is endles When the desktops themselves are not secure, then the security of their communication channels also becomes questionable How do we know that our e-mail is not being captured and read elsewhere? It may be fine if our mail is any regular mail, but what if it contains the details of a critical project ,or your financial data? Web browser security, too, has been an issue for sometimes There is a plethora of websites that can run malicious script on out machine the moment we click on a link Then, ofcourse, the safety of desktop hardware itself is becoming an issue A computer is made up so many small parts that anyone can easily put one in the pocket and walk off Notebooks are even easier to swipe as they are light and east to carry In the pages that follow we analyze most of these issues and talk about how we can secure our desktop and communication
THREATS FROM THE BROWSER:
Security web site was well designed and contained interesting links on how to protect our desktop from attacks, etc We clicked on one such link and that it was trap System went haywire, e-mail client automatically opened and started opening mail, applications started opening on their own etc All this happened with in a matter of a few seconds The web browser is an easy way for somebody to get into our system Most web browsers have configurable security settings So if we have a frilling that somebody is using our web browser to access our system, then push up the security settings of our web browser Set it to prompt we whenever a script request to be executed the number of scripts used by most web sites today This way, we can control the scripts we like to run on our systems
THREATS FROM E-MAIL:
Spanning and mail bombing are old hat Through they can still happen and cause problems, they happen upfront , so we can take preventive measures against them We can setup filters to delete mail off the server without downloading it, or use IMAP4 instead of POP3 for down loading our e-mail, which down loads just our mail headers and not the entire message, check with our e-mail headers and not the entire message, check with our e-mail administrator for IMAP support on our mail server It's quicker and since we can see all mail that's coming to our account, we can delete the unsolicited ones
However, what if we get an e-mail with an attachment from somebody we know? It can be invitation to a party from a friend of a mail from your boss asking we to check out a file It's a tough situation If it's actually sent by them, and we don't open it we might get into trouble with them later If it went from their mailbox unknowingly then the attached worm would wriggle through our desktop taking its toll So what should we do? Almost everybody recommends using a good anti-virus package with the latest update
The first thing to do is to check the date of the e-mail we received with the attachment Some worms use our address book and randomly pick an old message from our inbox and send it out to others So if it's a predated message then it's likely to be a worm You can confirm this by looking at the extension of the attachment If it's an odd looking at the extension we have never seen of an EXE then it's likely to be a virus KAK hta and navidad exe are the most recent examples If it's some sort of documents, then check whether the sender is reachable over phone and simply call up to find out In fact, that's the most convenient way to protect our desktop
THREATS FROM CHAT:
Though chat clients have been around for a long lime it was with instant messengers like ICQ that chatting become popular It's the most commonly used software we'll find on any desktop However, did we know that chat clients are one of the biggest threats to security? Apart from the regular instant messaging clients there ate several malicious clients like ICQ attack. These can get into any machine that has the ICQ client installed, and do anything. That’s why it's better to check the security settings in our client and configure it so that it doesn't remain online all the little but only when we want it to Now a days anti-virus programs are available just for ICQ
THREATS TO OUR DATA :
In this entire hustle and bustle to protect our system., the most basic entry point is often missed our That's the floppy drive Any body can walk up to our seat, place a floppy in our machine and implant a Trojan or worst still, supplies the hacker doesn't implant a Trojan but simply searches for all documents on our system and copies the important ones on to a floppy and walks off The most convenient protection against this is the screensaver password, which can word off most people However, such passwords are not very difficult to crack when it comes to a seasoned hacker In fact, somebody can also enter our system through the network if we have any shared directories So check to make sure threat only the directories we want are shared and not the entire drive We can also password protect them
Another solution that's gaining popularity is file and directory encryption Programs are available that let you encrypt any file lying on our desktop using the most robust encryption techniques Wonder crypt from wonder software technologies is one such software(WWW Wonder crypt com) It creates a public-private key pair for you and stores our private key on a USB based hardware storage device called the ikey We can also encrypt any file with our public key and decrypt it using our private key This is very secure as the private key doesn't stay in our system but remains with we safely inside the ikey So even if a person does get hold of crucial files he can't read them because they are encrypted
Another similar software is eloch which can lock any files we want to protect If encryption is not exactly our cup of tea ,then there are special hardware locks available that can lock up various parts of our PC like floppy drives , printers etc
THE BROWSER AS A SECURITY THREAT
In the beginning the web was a collection of static HTML pages To make the web more interactive, Graphical , and intelligent a number of technologies have been developed which can be embedded in HTML pages These include HTTP cookies Java applets , Java scripts , Active x components and more of their type We interact with all these when using a Web browser Though they do add welcome features to the sites, on the flip side , they also pose some threats to user We will also see how to configure Internet Explorer and Netscape Navigator for safe browsing
COOKIES
By definition Cookies are nothing but text files ,which are used to keep track of
a users preferences on a web site They can be used to present a customized interface to the user on his subsequent visits A simple example would be a site that lets you change its background color when you make a choice, say a blue background A cookie is sent by the web server to our browser The cookie contains in plain text the name of the item ,which is background Cookie is sent through a secure Socket layer
Cookies can potentially be used to track our preferences and build a profile ,which can then be used to target appropriate marketing messages at you
JAVA APPLETS
One of the reasons why Java become popular initially was due to its capability of adding Graphics and animation to web sites Java programs used in web sites which can only be run in a web browser are called Java applets In applications there is no security manager but in the case of applets an applet security manager comes into play The applet security manager does not allow the applets to read or write any file on our hard disk the applets can't make a network connection to any of the services running on your machine like a database They can connect back only to the server from where they were downloaded Applets can't access system information like user accounts, current directory and system environment variables Browsers have built-in JVM and applet security managers The applets run under the constraints of the browser's security manager, also called Sandbox
The restrictions of the security manager hinder the deployment of applets, which need some privileges or an intranet-like environment The solution to this is a signed applet Such applets embed a digital certificate (See article, what Digital Certificates in this issue) revealing the author or the developer of the applet The digital certificate is verified to be from a trusted CA and subsequently the applet is allowed to run with more privileges
CLIENT-SIDE JAVASCRIPT:
Java Script is a scripting language that runs within a browser, completely on the client side Some of its common uses are in checking whether an HTML form has been filled correctly, displaying a simple animation etc Java Script has no compatability to read or write files on the hard disk It can be used to send the read a cookie file Also a Java Script can communicate with a Java Applet
As you may have guessed , signed scripts have greater acc ess privileges and can even access local files Microsoft's answer to Java script is Jscript ,which adds some more features and works only in Internet Explorer
MICROSOFT ACTIVEX
Activex are software components don't run under a security model They are written using fullfledged programming languages like Microsoft Visual C++ and Visual Basic. Besides enhancing the browsing experience, ActiveX technology can be used to develop plug-ins to extend the capability of the browser. Only Internet Explorer supports ActiveX. Netscape doesn't have native support, but some third-party plug-ins are available to run ActiveX in Netcape.
Unlike Java, ActiveX componets don't run under a security model. They either run with full privileges or can't be run at all. The only authentication used for ActiveX components are again digital certificates.
ARE YOU REALLY SAFE?
As you might have noticed, a secure design goal has been followed by almost all these technologies. But unfortunately, that has been only in theory. In practive, there have been numerous bugs, which makes us suspicious about our privacy and safety on the Web.