Category Archives: Security

Types of Computer Security

Computer SecurityComputer security is that branch of information technology which deals with the protection of data on a network or a stand-alone desktop. As every organization is dependent on computers, the technology of its security requires constant development. Here are the different types of computer security.

Hardware Security

Threat
Even if the computer is not plugged into a network, a person can open its cabinet and gain access to the hard drives, steal them and misuse or destroy the data saved on them or, damage the device altogether. It is also necessary to remember that in case one dissembles his computer hardware, the risk of losing coverage of warranty becomes very high.

Protection
The security of computer hardware and its components is also necessary for the overall protection of data. If a stand-alone system contains some important or classified information, it should be kept under constant surveillance. Locking system for a desktop and a security chain for a laptop are basic security devices for your machine. Certain disk locks are available in various sizes, which control the removal of the CPU cover protecting internal components of the system. For example, you will find disk/tape drive lock, computer case lock with cable and padlock, security cables, etc. A disk lock guards all the internal access points located on the CPU and protects them.

Software Security

Network Security
Computer networks are an integral part of any organization these days, as they facilitate the free flow of data and services to the authorized users. However, such networks also pose a security threat in case the data is classified and confidential, thus making network security a vital necessity.

Threats
As the data is available only for authorized users, it is possible for hackers to pretend to be one, by providing the correct user name and password. Computer network security can be disrupted or encroached in the following ways:

Denial of Service
Denial-of-service is meant to disable a computer or a network and can be executed with limited resources. It is one of the most common forms of attacks by hackers and can effectively disable the whole network of an organization. Denial of service attack makes a computer resource unavailable to its intended user. To carry out this kind of attack, hackers generally flood a network or the access routers with bogus traffic. They also make attempts to disrupt connections between two machines and prevent individuals from accessing a service.

Trojan Horse
Trojan horse is common and one of the most potential threats to computer security. They are malicious and security-breaking programs, disguised as something which is considered as non-malicious by the security software. They are a useful tool for hackers who try to break into private networks. Hackers generally attach Trojan horse to a file, which triggers a virus or remotely controlled software, giving the hacker complete control over the computer.

Viruses and Worms
Viruses and worms are well-known for their destructive nature and the property of replicating themselves. They are basically pieces of computer program codes, which are written by hackers and other computer geniuses.

Sniffing
Sniffing is the act of intercepting TCP/IP packets while they are getting transferred on a network. The interception generally takes place through simple eavesdropping done by a hacker.

Protection
Firewall
It is one of the most essential type of network security in today’s world of Internet. Firewall is a filter that prevents fraud websites from accessing your computer and damaging the data. However, a firewall is not a great option for securing the servers on the Internet because the main objective of a server is granting access to unknown users to connect to various web pages.

Security Software
Along with firewall, try installing a good anti-virus and security software to enhance the security level of your computer system.

Data Security

Threat
Although uncommon, hardware malfunction can prove to be a major threat to your data in the computer. The life span of hard disks is always limited because of surrounding factors and this can amount to a severe loss of all your files saved on the disk, if there is no proper backup of those files made on any other system.

Protection
Keep Backup
It is important to avoid data and information loss in case of hard disk crashes. The only solution is to regularly keep backups of all the data on other media such as magnetic tapes, CD-ROM, etc. It is a good practice to store the media off-site and in case of a disk crash, restore the information from the backup media onto the new disk. In case a backup media is not affordable, one should try to store the files on at least two different media devices. These media devices should be systematically kept at a place which is safe and secured, as the information contained may be confidential. People usually have backup for database files, spreadsheet files and large documents. As the technical constraints are always there, it is better to take regular backups, in order to avoid any loss of information.

Clean-up Software
Install a software program on your computer that will clear all the old, unused files and registry keys. It will also help to detect malware and save your computer from a severe damage caused by it. Keep your system in the loop of latest updates and security alerts or else, it will become vulnerable to security threats.

It is important to keep a record of technical support consultants and software documentations, like manuals and guides to make them accessible to the staff members of the company.

Prevent Email Bombing

Email bombing is the process of sending large number of mails into someone’s mailbox, with an intent to affect the operating system of a computer or a network. It is also termed as email flooding, as the targeted mailbox is flooded with a barrage of mails. When your mailbox is flooded with unwanted and junk emails, your mailbox capacity will get exhausted and you won’t be able to receive any mails further. This action prevents you from reading the legitimate mails. It can even be used to completely overload any company’s mail server. It is done intentionally with an intent to affect the DOS (Disk Operating System) of a computer.

The intensity of email bombing can also result in crashing of the operating system and the mail servers. It has the capacity to consume the whole system. By limiting the user quota to a certain capacity, it can help to restrict its overflow. The hacker aims to shut down the website of a victim, by sending email bombs. The first known incident of email bombing was done by Tamil guerrilla groups against the Sri Lankan government. Tamil guerrillas swamped the system of Sri Lankan embassies with an email containing the message ~ “We are the Internet Black Tigers and we’re doing this to disrupt your communications”.

Causes of Email Bombing

Overloading of the network connection
Loss of connectivity
Denial of service
Consumption of all system resources
Syslog entries

Preventive Measures

Use Proxy Servers
If the email bombs are incoming from many IP addresses, it’s difficult to spam and filter each and every mail from those addresses. In this case, employing proxy servers will help to minimize the problem. The computers in a particular network, will be connected to a proxy server, which is another computer. The client computers request for information and resources of other computers, to the proxy server. The proxy server addresses the request and sends the information, after filtering the messages which is done according to the filtering rules of the proxy. It checks for malware content and filters the messages from suspicious IP addresses and protocols before transmitting it to its clients. In this way, proxy servers, protect the network and also take on the complexity of the computer networks.

Monitor Simple Mail Transfer Protocol
Simple Mail Transfer Protocol (SMTP) is a method of authenticating the exchange of messages that are transmitted or received across the Internet protocols. The clients in the network use Post Office Protocol (POP) or the Internet Message Access Protocol (IMAP), of their system to access their mailbox. The Mail Submission Agent, sends a mail or transfers any information to the Mail Transfer Agent (MTA), through SMTP. The MTA connects to the SMTP and then analyzes the mail exchange record and the IP address of the sender, and then only accepts the message. Security mechanisms such as authentication and negotiation are processed during the exchange of data. Internet Engineering Task Force (IRTF), is working on the authentication process and finding ways to strengthen this system, as the complexity of the system is growing rapidly.

Use Mail Filter Applications
Filter packages are exclusionary schemes that are used to filter the mails according to the source addresses. For windows and Mac OS computers, I have listed some filter package tools below.

EIMS (Mac OS)
Mail Siphon (Mac OS)
Musashi (Mac OS)
SIMS (Mac OS)
Email Chomper (Windows 95/85/NT)
Spam Buster (Windows 9x/ ME/ NT/ XP/ 2000)
SpamKiller (Windows 9x/ ME/ NT/ XP/ 2000)

How Can You Do Against Email Bombing?

Identification: If your system becomes sluggish or if you are not able to send or receive mails, it could be because your mailer is trying to process many number of mails.
Reaction:
If you find an email bomb, configure your router using your Network Service Provider, after identifying itssource.
Update the current version of your email delivery software.
Spamming the emails may also help to some extent. But it is never the permanent solution.
Prevention: Configure your mail handling system and firewall, properly. Most importantly, don’t propagate the problem by replying to the spammed mails.

Examples of Email Bombs and their Filenames

Anyway, it won’t help you to prevent email bombers from attacking your computers, but if you are running a network having multiple users, then you can check these filenames in the hard disk drives of your network and thereby you can prevent your users from attacking other computers by email bombing. Take a look at the list.

Email Bomb Filename
Kaboom kaboom3.zip, kab3.zip
Gatemail gatemail.c
Avalanche alanch3.zip, avalance.zip
Ghost Mail gn51.zip
Euthanasia euthan15.zip, et15.zip
Aenima aenima17.zip, aenima20.zip
The Windows Email Bomber bomb02b.zip
Unix Mailbomber mailbomb.c
Haktek hatetuk.zip
The Unabomber unabomb.zip, unz.zip
Up Yours upyours3.zip, up4beta3.zip
Serpent (Linux) serpent.zip

Identifying the IP address from which the email bomb is received and directly contacting the postmaster is also an effective way to prevent it. They can also lead to malfunctioning of the mail servers and also results in denial of service. One such case occurred when a hacker bombed the systems in Monmouth University in New Jersey, which caused temporary halt of the whole mail server.

There are many instances of email bombing, one of which even affected the NATO computers in the year 1988. The whole network of The Institute of Global Communications (IGC), was attacked by email bombers for creating the online publication of Euskal Herria journal, for supporting and writing about Basque separatist movement, which was very active during the time. One thing to be kept in mind is, these are just preventive measures. There is no permanent solution to completely getting rid of email bombs.

Prevent Phishing Attacks

Prevent Phishing AttacksRemember when your parents would warn you about talking to strangers, telling them where you live and taking things from them? Well, the Internet is another “stranger” filled place, with hidden threats lurking around each site’s corner. Along with the obvious bad guys like viruses and malware, a sneakier threat is phishing attacks, which are likely to rob you blind and take your identity too.

What is phishing exactly? Without all the technical lingo, a nefarious site or person (“phisher”) pretends to be a legitimate site to steal your personal information or financial records. So you think you are logging into your online bank account but you are actually logging into a very craftily disguised site, that stores your login info to access your account. The term “phishing” is a word play on “fishing”, where a fisherman baits his hook, fools the fish into thinking it is food and reels it in. Such tactics are a serious threat to online safety and individual users security. Below are some tips to prevent phishing from stealing your information.

Top 10 Tips to Prevent Phishing Attacks


Read emails and messages carefully. Instinctively one’s first tendency is to “click, open, delete”, don’t follow such instincts. Go through the email completely. Look for some tell-tale phishing signs such as:

Spelling mistakes and grammatical errors in the email’s text
Your name isn’t present anywhere but instead a general name is given. (“Dear satellite subscriber”, instead of your full name heading the email)
Subtle threats to follow the email’s instructions (“your account will be terminated if you fail to follow the procedure”)
Unknown senders or companies you have never heard of
Impossibly unrealistic deals (“a wealthy millionaire died and decided to leave you, Mr. Abc, all his money”)


Verify the authenticity of the email sender. If an organization like a bank or company is trying to contact you, whether known or unknown, you should contact that organization personally and verify that they have sent you the mail. Phishing sites are like chameleons, they do their best to simulate or imitate legitimate sites, to look authentic. Do not use any phone numbers provided in the email. Remember that most legitimate sites and financial services will never deal with sensitive issues in emails.


Do not click on links in your email at first. Hover the mouse icon over the link and see what address appears in your browser screen. The text of the link can say one thing but the actual address could be someone’s private computer or fake website. For e.g.: the link could be: http://www.xyx.com but on hovering, the text might read: http://192.123.123.12/fileen.htm or http://192.123.255.12/collect.exe. Do not copy the URL or link and paste it in your browser’s address bar. To truly test its authenticity, open a new window and type in the official site address of the organization or company. Phishing sites will use legitimate looking links to fool you into clicking and then take you somewhere else entirely. Do not click on links in pop-up windows at all.


Avoid sending private information like your name, account details, passwords – any sensitive information that is unique to your online identity, through emails. Your email account or the recipient’s account could get hacked and your information exposed.


Do not enter any information in pop-up windows. With downloads and attachments, be vigilant. Only open or download email attachments from known senders but make sure you scan the attachment prior to download, using your anti-virus software.


Check any of your online or financial accounts and transaction statements for any suspicious activity or operations. For example, if there has been a deduction from your bank account which you have no knowledge of or a “password successfully changed” alert appears on your phone, contact the respective department of the company involved and assert that you have not performed said changes. Such checking of accounts should be done at least once a month.


Your computer is your castle, so line its defenses with spam filters, anti-spyware programs and a decent firewall. Look for anti-virus programs, with phishing filtering. Download the latest security updates and keep your computer up-to-date, so that it can handle the latest threats as they come.


If you are carrying out sensitive data transactions like online shopping or money transfers, make sure you are using a secure connection to a secure site. So look for “https://” in your address bar, before the site’s address. Another sign is in the bottom right-hand side of the web browser. A small chain or yellow lock icon indicates a secure connection. Sometimes such icons can be “faked”, so check the URL of the site as well. Clicking on the lock icon should display the site’s security certificate. If the site name and the name of the site on the certificate do not match, leave the site immediately.


With phishing being such a silent yet deadly web menace, web browsers are also stepping up their security mechanisms. So install a tool-bar or phishing filter utility on your browser to warn you from navigating to phishing sites. Turn on your browser’s security mechanisms and alert messages. Updating your browser will also keep such security features informed of the latest threats.


If you suspect a site of being “phishy” or you have been phished”, then your silence will just allow the guilty party to scam someone else. Some web browsers allow you to report suspected sites or mark them as unsafe. You can even inform the legitimate site being impersonated of the phishing site. The Federal Trade Commission deals with phishing scams and sites dealing with such attacks, visit their site to complain of such sites and if you are a victim, then informing the FTC can help prevent the possible theft of your identity.

Don’t fall for the “hook”, be the smart fish that got away by following the right anti-phishing tips. It is web hooligans like phishers and hackers, that give the Internet a bad name, so surf smart and access secure information smartly.

Basic Computer Security Tips

Everyone talks about computer security i.e being secure online but how many of us actually practice the effective security tips? Then when hackers or viruses attack, we look around to attach blame. Well, prevention is better than cure, so it pays in the long run to secure your system in advance.

Tip #1: Set up user accounts
One computer, many users, is a security disaster waiting to happen. Your files and data are your personal, private content and should be protected accordingly. To prevent other users from seeing or accessing your data, set up user accounts on your PC. A user account shows an individual’s specific data and not what is present on the entire system. It also specifies privileges on shared data, such as deleting/editing operations and what software can be installed on the machine.

This feature is especially useful when kids and adults use the same machine. What if your child accesses your important work files and deletes them by mistake? With a separate user account, he/she can only view certain files and cannot modify or delete them. Even if you are the sole user of the PC, set up a guest account, in case someone else needs to use the computer.

Tip #2: Secure your wireless network
With wired Internet access, there’s little risk of someone encroaching on your network. But wireless networks do have holes in their security, so as the owner of the network, you need to be vigilant. Setting up password-protected network access is the first step. You need to assign a network name and password to your Wi-Fi network. Use the latest wireless encryption methods like WPA or WPA2. Do not reveal your network password to others.

Tip #3: Arm your computer with an anti-virus program
The best defense is a good offense. One of the most basic computer security guidelines is installing an anti-virus software. Installing security programs like an anti-virus, keeps your computer round-the-clock safe against viruses, malware, Trojan worms etc. and other malicious programs. For better protection, try to install complete security suites, that provide Internet security and firewalls along with anti-virus software.

Tip #4: Be regular in updates and virus scans
Just installing an anti-virus program will not protect your PC. You need to keep it up-to-date with regular virus signature and threat updates. New viruses and malware programs emerge online each day. Another bad trait of viruses is that they keep trying to find new ways to enter an unsuspecting computer. The only way to counter such attacks is to update your security programs on a regular basis. You should also scan your computer regularly for dangerous programs. Schedule periodic scans, once-a-month scans, scanning new added devices and automatic full system scans, to ensure your PC is threat-free.

Tip #5: Install parental control software for kid-friendly computer usage
Keeping your computer secure definitely involves keeping your kids safe from cyber enemies. Aside from explicit and adult content, you need to filter and monitor what your kid is up to online. Social networking sites in particular, are fun online places to socialize but they are also preying grounds for the depraved. Parental control software allows you to set filters and block sites as well as receive warnings when suspicious activity is taking place online.

Tip #6: Block unwanted search results
You can even change your web browser’s security settings to block certain sites and filter out objectionable content. Such settings are not as powerful as parental control software but it helps to be extra secure. You can find this feature in the Tools option of most browsers. With search engines like Google, you can fiddle with search preferences settings.

Tip #7: Download wisely
Whether it is a picture, an MP3 or a game, downloaded files are an excellent way for malicious software to enter your computer. Once you download and install or use a file, there’s no telling what it will do to your machine. So be extra careful when it comes to downloading. Download files from trusted and preferably certified sites. Sites offering free, cracked versions of software programs are especially dangerous, as some cracks can contain malware.

When a download begins, you are asked to save the file before the downloading actually starts. Read the file name and its extension carefully, to ensure what you want is being downloaded. While installing a program, read the license agreement and make sure, only the program you want is being installed. Sometimes spyware and hidden programs are bundled into the installer program, and are installed secretly along with your software. Scan your PC for threats after downloading files from the Internet.

Tip #8: Be careful with emails
Getting and sending emails is easy, going through your inbox for mail, that is actually relevant, is not. Email inboxes are storehouses of junk mail, spam, advertisements, forwards, mail and many times, a hidden threat. You can keep your inbox sorted and clutter-free by using spam blockers and filters. Threat-wise, try to avoid opening emails from senders or addresses you don’t know.

A key sign of a malicious email is poor language. Weird, nonsensical text or poor grammar or even bogus-seeming email addresses are some signs of a harmful email. Be especially wary of email attachments. Check the file extension. Files with .exe, .pif, .com,.bin or .bat extensions, can be malicious. If you do not know the sender of the email, do not open or download such files, just delete the mail. Instead of opening the attachment from the mail itself, save the file, let it download and scan it, before opening it.

Tip #9: Secure your data with backups
Sometimes no matter what steps you take, you lose data. Part of being secure is having a fail-safe or backup to fall back on, in case something bad happens. So in case a virus has attacked your files or data is accidentally deleted, your data is never really lost, if you have a backup of it. Backup your data regularly, either by storing it on physical devices like CDs or by backing it up on a network. Set a system restore point for your PC, so in the event of a system crash, you can restore your PC to a particular working state with your data intact.

Tip #10: Be smart with your passwords
Passwords are supposed to keep your individual settings and data safe, so you need to keep their true value or the actual password safe. This means, do not write down all your passwords on a piece of paper and keep it lying around. With numerous passwords, it’s understandable that remembering them all is difficult. So you can write them down but the place where you store this info, should be secure. And once in a while, please change your passwords. If in case, they are revealed, updating the passwords can render all hacking attempts as naught. Another safety precaution is the “remember me” option in most secure sites. If multiple users access the same PC, do not select this option.

The above computer security tips are just the tip of the iceberg, when it comes to securing your PC. For every good advancement in technology, cyber evil seems to get even more evil, so it pays to be vigilant in today’s cyberspace.