Internet Security

facilities for secure communication

MALWARE

• Malware refers to any program or computer code deliberately designed to harm any portion of a computer system

• The three most common forms of malware are viruses are viruses, worms and trojan horses

• Morris worm was created in 1988 and infected 6,000 computers using the UNIX operation system.

MALWARE COUNTERMEASURES

• Antivirus– Signature scanning: a virus signature is a string of

binary code unique to a particular virus. Virus signatures are also known as fingerprints or patterns. Because new viruses appear all the time, a virus program’s signature file must be updated frequently to maintain the program’s ability to defend against threats. Many antivirus programs will automatically inform users when a new virus signature update is available for download.

• Disadvantages of signature scanning– Polymorphic viruses change with each replication.

The constantly changing signature of a polymorphic virus makes it more difficult to detect using signature files alone.

– Signature scanning also is ineffective against new viruses for which signature updates do not yet exist

– It detects malware only after it has infected a computer system

• Heuristic scanning looks for general malware characteristics rather than specific characteristics such as a signature.

• Heuristic problem solving relies on previous experience or knowledge.

• An antivirus program that uses heuristic scanning examines file size, architecture, or code behavior.

• Heuristic scanning can produce false positives and negatives.

• For e.g.. It might report a legitimate software program as malware on the basis that it shares some characteristics with known malware programs.

• Just as with signature scanning, heuristic scanning software requires periodic updates to ensure that the catalog of suspicious characteristics is up to date.

• Behavior Blocking looks for typical malware behaviors, such as attempts to change computer settings, the opening and or alteration of files, attempts to open computer ports etc.

• Ports are computer doorways used for various activities, and an open or unguarded port can be the entryway for malware.

• It is becoming popular since hackers face greater difficulty changing the behavior of malware than changing a virus signature

FIREWALLS

• It is a hardware or software barrier located between the internet and a computer or computer network. Many routers available nowadays contain built-in firewalls

• A firewall is a system of hardware and software that connects the intranet to external networks, such as the internet. It blocks unauthorized traffic from entering the intranet and cal also prevent unauthorized employees from access the intranet

• Two components of firewalls are a proxy server and caching.

• Proxy server is a server, or remote computer, that may exist outside of the organization’s network, ad all communications to the organization are routed through it. The proxy server decides which messages or files are safe to pass through to the organization’s network. It can also provide document caching

• Caching is to store copies of web pages for quick access; the purpose is to speed up the web for their users. The only difficulty with this practice is that the original web page may have been updated, but this is not reflected on the copy in the cache in the proxy computer.

Firewalls

• Routers available nowadays contain built-in firewalls.

• A firewall filters data arriving through the internet to protect the system from any threats.

• Firewalls can be configured to reject incoming packets based on the IP address or domain name they originate from.

• This prevents the entry of data from sites known to harbor threats.

Firewall• A user can configure a firewall to allow or disallow the

use of different protocols e.g. restricting FTP to prevent unauthorized file transfers from taking place.

• Firewalls can also filter incoming packets for text they might contain.

• Start with the highest level of security when you configure a firewall. If it creates problems denying access to legitimate data, adjust the configuration until an appropriate balance between security and convenience is achieved

• Firewalls can help prevent malware but antivirus are also needed.

Service Patches and updates

• It’s important to install security patches.

Password protection

• Passwords help protect your computers

CYBER CRIME

• It refers to crimes committed using the internet.

• Some cyber crimes are phishing/spoofing, 419 scams, DOS attacks, brute force attacks

Phishing

• It is when an online scammer sends a user an e-mail that appears to be from a legitimate and well-known company to try to trick the user into sending confidential information.

• The practice of disguising an e-mail or a web site so that it appears to belong to a well-known company such as yahoo, Google or others is called spoofing.

Phishing

• The e-mail typically lists a URL that will direct victims to a spoofed web site that gives every appearance of being the legitimate web site of a familiar company.

• Many users recognize phishing attempts by noticing obvious spelling or grammatical errors.

• Current phishing attacks are estimated to have a 3% success rate.

419 Scams

• The 419 scam, or advance fee fraud, is a very popular cyber crime committed using e-mail.

• This scam gets its name from a section of the Nigerian penal code, because the vast majority of this type of crime originates in that country.

• E.g. have to pay money to attend a seminar or has money and needs help etc.

DOS attacks

• Sending a lot of traffic to deny the network from functioning.

• DDOS (distributed denial of service), a Trojan horse is used to download a small program onto an unsuspecting internet user’s computer. The program transforms the computer into a zombie that is used to send messages to the target of coordinated DDOS attack.

Brute force attacks

Cyber crime countermeasures

• Internet explore security settings• Encryption and authentication– Symmetric and asymmetric encryption– Digital certificates– Digital signatures– Secure sockets layer (SSL) protocol

• Biometric authentication

Threats to privacy

• Spam• Adware/spyware• Cookies• Inappropriate content

Privacy countermeasures

• Spam blocking methods• Spyware/adware avoidance• Cooking blocking• Parental control software