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Intentional attacks on computing resources and networks persist for a number of reasons

Complexity of computer software and newly emerging hardware and software combinations make computer and the network susceptible to intrusion ◦ It is difficult to thoroughly test an application for all

possible intrusions

1. Trojan horse programs2. Back door and remote administration programs3. Denial of service4. Being an intermediary for another attack5. Unprotected Windows shares6. Mobile code (Java, JavaScript, and ActiveX)7. Cross-site scripting8. Email spoofing9. Email-borne viruses10. Hidden file extensions11. Chat clients12. Packet sniffing

Source: CERT

Trojan horses are programs that are installed without the knowledge of the user

Trojan horse programs can perform a wide variety of covert talks such as modifying and deleting files, transmitting files to the intruder, installing programs, installing viruses and other Trojan horse programs etc.

Covert installation of remote administration programs such as BackOrifice, Netbus and SubSeven

Such programs give remote access to the computer from anywhere on the Internet

Client computer is used to launch mostly denial of service attacks on other computers

An agent is usually installed using a Trojan horse program to launch the denial of service attack on other computers

Malicious code can be stored in protected Windows share for propagation

Mobile codes in Java, JavaScript, and ActiveX can be executed by a web browser is generally useful, but it can also be used to run malicious code on the client computer.

Disabling Java, JavaScript, and ActiveX from running in the Web browser must be considered when accessing websites that cannot be trusted

Email received in HTML format is also susceptible to mobile code attack because it could also carry the mobile code

A malicious script can be sent and stored by a web developer on a website to be downloaded by an unsuspecting surfer

When this website is accessed by a user, the script is transferred to the local web browser

Ways of acquiring malicious scripts include “following links in web pages, email messages, or newsgroup, using interactive forms on an untrustworthy site, viewing online discussion groups, forums, or other dynamically generated pages where users can post text containing HTML tags” - CERT

Email “spoofing” tricks the user in believing that the email originated from a certain user such as an administrator although it actually originated from a hacker

Such emails may solicit personal information such as credit card details and passwords

Examining the email header may provide some additional information about the origin of the email

Malicious code is often distributed through email as attachments

Attachments must thus be opened with caution

An attachment may have a hidden file extension◦Such files may execute the attachment

Examaple: ◦ Downloader (MySis.avi.exe or

QuickFlick.mpg.exe)◦ VBS/Timofonica (TIMOFONICA.TXT.vbs)◦ VBS/CoolNote

(COOL_NOTEPAD_DEMO.TXT.vbs)◦ VBS/OnTheFly (AnnaKournikova.jpg.vbs)

In the above files, the hidden extension is .vbs pertaining to an executable Visual Basic script

Internet chat applications such as instant messaging applications and

Internet Relay Chat (IRC) involve the exchange of information including files that may contain malicious executable codes

The same caution that applies to email attachments apply here as well

Packet sniffer programs capture the contents of packets that may include passwords and other sensitive information that could later be used for compromising the client computer

For example, a sniffer installed on a cable modem in one cable trunk may be able to sniff the password from other users on the same trunk

Encryption of network traffic provides one of the defenses against sniffing

Many businesses rely heavily on computers to operate critical business processes

Individuals are using computers for tasks that required confidentiality

Advent of Internet has provided a physical path of entry for every computer connected to the Internet ◦An always connected broadband connection is

always vulnerable in this case

Providing security requires action on two fronts, namely the management and the technical fronts respectively

The management aspect relates to organizational policies and behavior that would address security threats and issues

The technical aspect relates to the implementation of hardware and software to secure access to computing resources and the network

Best practice approach is to ensure secure behavior The above can be done by established guidelines for

managing, addressing and rectifying security related issues

Introduce security related hardware and software to secure access to computers and computing resources

From an implementation point of view, the following are some of the steps that could be taken to provide security◦ Implement security patches and other updates

pertaining to an operating system and other venerable software such as the Internet Explorer

◦ Install self-monitoring an anti-virus, anti-spam and anti-hacker and pop-up blocker software

◦ Install a firewalls◦Use encryption wherever feasible

All the approaches can be used to complement one another

Security patches are issued by mainly the OS vendor such as Microsoft to patch security holes as they are discovered

Examples of self-monitoring software include anti-virus, spyware elimination, pop-up blocking, and anti-spam software

Both the security patches and the self-monitoring software act at the local client level

Antivirus◦Mcafee

Spyware elimination Pop-up blocker Anti-Spam

Firewalls are used for controlling access to the computing resources

In general, it acts at the network level controlling network access to computing resources

Firewalls can be implemented in software as well as in hardware

By encryption, the data can be made illegible to the intruder

It can be implemented at the network level as well as the client level

For example, locally stored data can be encrypted and the network traffic could equally well be encrypted

VPN PKI Digital Certificates

Firewalls and encryption will be discussed further in separate modules under the section entitled “Network Security”

firewall.com firewall-net.com firewallguide.com msdn.microsoft.com winroute.com tinysoftware.com sunsite.unc.edu

http:// www.howstuffworks.com http://www.microsoft.com http://www.securityfocus.com http://grace.com/us-firewalls.htm http://www.kerio.com/us/supp_kpf_manual.html http://www.broadbandreports.com/faq/security/2.5.1. http://www.firewall-software.com

http://www.tlc.discovery.com/convergence/hackers/hackers.html

http://www.tuxedo.org/~esr/faqs/hacker-howto.html http://www.iss.net/security_center/advice/Underground/

Hacking/Methods/Technical/ http://www.infosecuritymag.com/articles/march01/

features4_battle_plans.shtml http://www.nmrc.org/faqs/www/wsec09.html http://www.microsoft.com/. Tim Rains • Technical Lead • Networking TeamTim Rains • Technical Lead • Networking Team

Q310099, "Description of the Portqry.exe Command-Line Utility"