Showing posts with label network security. Show all posts
Showing posts with label network security. Show all posts

Friday, November 20, 2009

Basic of Network Security


There are two key information security or safety information: First, configure the system and the network correctly and keep it that way. Because it is not possible to do it perfectly, the second key in information assurance is to know the traffic entering and leaving your network.That way, if something terrible happens, you can detect . Therefore, all tasks that have to do in network security are divided into three phases or classes:

  1. Protection, where we configure our systems and networks as correctly as possible
  2. Detection, where we identify the configuration has changed or that some network traffic indicates a problem
  3. Reaction, after identifying quickly, we respond to any problem and return to a safe state as rapidly as possible


Because we can not guarantee perfect security, we must accept a certain level of risk. Risk is defined as the probability that a threat will pass through the vulnerability. The risk is difficult to calculate, but we get a rough idea considering our attack surface, exposure and vulnerability accessible and more usable than we have. A vulnerability scan or penetration test helps us to measure or define our attack surface. One thing we do to reduce our risk and improve our chances of survival is to use multiple defenses. There are five basic architectures to develop a defense in depth.


The uniform method of protection for defense-in-depth
generally involves a firewall separating the internal trusted zone from the Internet, most implementations have anti-virus in the mail store and forward on the servers and desktops. It generally means that all internal hosts receive the same level of protection from attack by the computer network infrastructure. It is the most commonly and easily implemented architecture and least effective in terms of achieving a high degree of information assurance unless all IT contained information assets are of equal importance to the organization.


Information Centric
.
Adm. Grace Hopper, a famous early researcher in computing said, "Some day, on the corporate balance sheet, there will be an entry which reads, 'Information'; for in most cases, the information is more valuable than the hardware which processes it.it is critical to understand and to be able to help others understand the value of information. In addition to richly valuable information such as intellectual property (patents, trademarks, copyrights, know how, data schema), there is also data including the increasingly important business record. To build an information centric defense-in-depth architecture, we must locate our critical and valuable information and ensure the proper protections are in place. This used to be very costly and was avoided, but due to changes in the Federal Rules of Discovery, many organizations have to build process to locate all information and tag it, so this becomes much easier.


Threat Vector Analysis
Defense-in-depth is similar to information centric; it requires us to identify the assets we want to protect in order of priority, perform an analysis to determine the paths the threat could use to reach the vulnerability and figure out how to place controls on the vectors to prevent the threat from crossing the vulnerability.

Protected enclaves
Simply means subdividing the internal network so that it is not one large zone without internal protections. This can be done with firewalls, VPNs, VLANS and Network Access Control.

Cryptography
When defense in depth fails, the only remaining protection for the data is cryptography. Cryptography is very strong: if your organization is using a modern algorithm, the encrypted information is so powerfully protected, the encrypted data cannot be attacked. However, the processes we use to manage the crypto keys can be attacked, so strong processes related to key management are a must. As an example, many organizations have purchased full disk encryption for their laptops. There is no way to reverse that encryption without the key. However researchers at Princeton recently demonstrated ways to capture the key from memory defeating the protection with many vendors products.There are three types of cryptography algorithms: secret key, public key, and hash functions. Unlike secret key and public key algorithms, hash functions, also called message digests or one-way encryption, have no key. Instead, a fixed-length hash value is computed based on the plaintext that makes it impossible for either the contents or length of the plaintext to be recovered. The primary application of hash functions in cryptography is message integrity. The hash value provides a digital fingerprint of a message's contents, which ensures that the message has not been altered by an intruder, virus, or by other means. Hash algorithms are effective because of the extremely low probability that two different plaintext messages will yield the same hash value.

Access, Authentication, Authorization
Sometimes called Triple A or AAA, these are the keys to implementing security in the organization. Access process should ensure the correct person is accessing your organizations computing and networking resources. Since passwords can be shared, many organizations use a physical token in addition to a password during the authentication process. Once authenticated, controls should be in place to make sure individuals only access the resources they are authorized to access.

Separation of Duties, Separation of Services
Separation of duties is a common policy when people are handling money so that fraud requires collusion of two or more parties. This greatly reduces the likelihood of crime. Information should be handled in the same way since it can be bought and sold easily. If your system administrators claim that their duties cannot be broken up, it is important to understand well run organizations do just that.A long time ago, servers were so expensive that a single server would run multiple services. One of the lessons we learned from the first worm (malicious software that spreads by breaking into systems) was that if a server crashed with multiple services running on it we would lose the ability to supply all of those services. For the next ten years, it was considered good practice to have one service per machine; a mail server, a file server, and so forth. Today, with virtual machines and service oriented web architecture, we are moving back to multiple services, in fact far more services than before. This is fine as long as we factor in how to keep operating if something bad happens to that machine. There are fields of study called continuity of operations, disaster recovery and business impact that provide insight into these fields of study.

Role-based access control (RBAC)
is an access control method that organizations implement to ensure that access to data is performed by authorized users. Unlike other access control methods, role-based access control assigns users to specific roles, and permissions are granted to each role based on the user's job requirements. Users can be assigned any number of roles in order to conduct day-to-day tasks. For example, a user may need to have a developer role, as well as an analyst role. Each role would define the permissions that are needed to access different objects.[4] With Network Access Control we can extend this from groups on systems to the entire enterprise. It requires more configuration than protected enclaves, but it yields more protection.

Web, Web Browsers and AJAX
Odds are very high that your organization is spending a lot more money on webmasters, web programmers and the like than you were just five years ago. Most software application development is becoming focused on the web for delivery. This means that most of the information entering and leaving the majority of user computers is via the web. However, web browsers such as Internet Explorer were not purposely designed as security gateways. It is possible to attack a users computer via their browser. Until security becomes the most important priority for web browsing software, problems will continue to exist. This is going to be especially true with the new web 2.0 interfaces that use recently developed extensions to a programming language web browsers support called AJAX to deliver enhanced functionality, but at the cost of increased risk.

Endpoint Security and Ubiquitous Computing
Wireless networking continues to grow, entire cities are connected with metropolitan wireless, if you have a PDA or advanced cell phone you are connected to the Internet at all times. These devices can communicate with your desktop or laptop computer via Bluetooth. Organizations are going to have to engineer security at the device itself, this is called endpoint security. It is no longer possible to believe in a security model where you are fairly safe because we are connected to a corporate LAN protected by a firewall and an intrusion prevention solution. Rather, we need to consider security in a ubiquitous computing paradigm, always on the Internet wherever we are.

SOA and the Future
Web based programs are very complex to create and maintain because they potentially offer so much functionality. For instance, if you have an online stock trading account, you can research, trade, run financial reports and even do online banking. To manage complexity and make it possible to get product to market faster, organizations are learning to simply create atomic services. This is known as Service Oriented Architecture (SOA) and may one day be the primary tool to support mission critical applications. If your organization needs a service, it consults a directory called UDDI to find it. This is similar to using a search engine like Google, but programs do this without human intervention, at least that is the idea.

SOA offers and exposes more business logic than a regular web server, after all each and every service you offer has to be in the directory if you want client programs to find you. A big part of the security battleground of the future will be centered around SOA, limiting the unauthorized release of sensitive information and creating gateways and other tools to protect the services.

By Richard Anderson

Thursday, November 19, 2009

E-mail Security Basic


Simple to implement, these tips may be a good start to ensure your communication by e-mail is safer.


1. Understand that no communication by e-mail is 100% secure. We do our best to make the percentage close to that, but sometimes - if the information is extremely important - you should consider ditching e-mail option and submit it in person (if possible). Do not send credit card or social security numbers by e-mail. It is also a good idea not to send usernames and passwords for accounts you do not want compromised.

2. Linked to the notice is as follows: select text in HTML or XHTML refunds to reduce the risk of being targeted by a phishing attack.


3. Plus your e-mail address is present in the precincts of cyberspace, the more spam you'll likely receive. Unfortunately, even if you pay attention to disclose your e-mail, chances are people that you include in mass mailings and we end up in your e-mail will be there. To counter this, you must set up filters and rules. They will not catch all the junk mail, but they will reduce their number. This is not just a question of nuisance - basic users and novices are more susceptible to spam and scams. So why do "bad" opportunity to judge their angle?

4. Use encryption. Check with your ISP to see if they encrypt the authentication process. Encrypt your e-mail if possible. Are you familiar with the concept of steganography? You can hide messages in images, commercial items, lists ... Ideally, you can use both - first encrypt the message, then use a steganography software to integrate a recent photograph. There are simple tools out there.

5. Do not access your e-mail from an unsecured network or potentially compromised computers. Yes, this includes in particular access from an Internet cafe. There have keyloggers.


6. Lessons for those who want to know about this, especially to children (and especially if you use the same computer).


7. Do not open attachments unless you know who he is and you trust it.


By Adam Addison

Wednesday, October 7, 2009

Protecting Your Network from Hackers, Viruses and Malicious Software


If you have a server base network, it's critically important to protect your server from hackers, viruses, and other malicious software. If your server is compromised, it can jeopardize the safety and security of your company's entire network and all its data. Here are some ways you can protect your network against attack:

Your server has built-in security features.
Use them. If configuring your server's security settings is beyond the scope of your technical expertise, hire an expert to do it. While this will cost you a little more up front, the price you'll pay to secure your network is miniscule when compared to the cost of responding to and recovering from a hacked server.

Firewalls are essential.
Software firewalls are sufficient for small networks, but if your network is large or spread out, you may want to run a hardware firewall in conjunction with your server. A hardware firewall will control access to your network's computers from a single point, making it easier to monitor, and theoretically, more secure. But at the bare minimum, your server needs a software firewall.

Software patches are vital to server and network security.
When a new threat emerges, be it a virus, worm, or Trojan horse, antivirus software developers issue software patches, or updates, that close up the security hole that the malicious program has exploited. If you're running an old version of a server operating system, your server could be vulnerable to attack. Not having the latest version of your server's software installed is akin to not getting immunized against eradicated diseases; the cure is out there, but you just haven't bothered to take your medicine.

Unrestricted server permissions and passwords should be given to as few people as possible.
Use strong passwords, and keep them strictly confidential. (For more information on developing password protocol for your business.

Physical security is just as important as password security, if not more so.
Protecting your servers from the elements — and criminals — is essential. A closet is usually perfect for one or two servers; no windows and a single locking door reduce the chance of your servers being damaged. Lock up the room or closet whenever it's not in use, and distribute keys only to employees who absolutely need them. Also, store your server computers up off the floor, either on special racks designed for that purpose, or in some other manner, to keep them from being damaged by floods or leaks.


By David Christofer