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In your car, the firewall sits between the engine compartment and the front seat and is built to keep you from being burned by the heat of the combustion process. Your computer has a firewall, too, for much the same reason – to keep you and your data from being burned by hackers and thieves who are the unfortunate creators of “Internet combustion” and destruction.

The firewall, a “combo” approach of software that regulates and monitors hardware and communications protocols, is there to inspect network traffic and all the “packets” of information that pass through to your inner sanctum, your CPU and hard drives. A firewall will rule out the possibility of harm, or at least greatly minimize, by noting and quarantining potentially harmful “zones” and will either deny or permit access to your computer based on the current set of rules that applies at the time, depending on many (very many) factors.

Basic tasks and settings

The basic task for a firewall is to regulate of the flow of traffic between different computer networks that have different “trust levels.” The Internet is full of countless overlapping zones, some safe and some totally deadly. On the other hand, internal networks are more likely to contain a zone or zones that offer a bit more trust. Zones that are in between the two, or are hard to categorize, are sometimes referred to as “perimeter networks” or, in a bit of geek humor, Demilitarized Zones (DMZ).

Without proper configuration, a firewall can simply become another worthless tool. Standard security practices call for a “default-deny” firewall rule, meaning that the only network connections that are allowed are the ones that have been explicitly okayed, after due investigation. Unfortunately, such a setup requires detailed understanding of network applications and a great deal of time and energy to establish and administer.

Who can do what?

Many businesses and individuals lack sufficient computer and network knowledge to set up a default-deny firewall, and will therefore use a riskier but simpler “default-allow” rule, in which all traffic is permitted unless it has been specifically blocked for one of a number of possible reasons. This way of setting up a firewall makes “mysterious” and unplanned network connections possible, and the chance your system may be compromised becomes much more likely.

Firewall technology had its first growth period in the computer technology revolution of the late 1980s, when the Internet was a fairly new in terms of its global reach and connectivity options. The predecessors to today’s hardware/software hybrid firewalls were the routers used in the mid 1980s to physically separate networks from each other. However small the Internet began, it was ultimately undone by supremely fast growth and the lack of security planning, and therefore there were the inevitable breaches caused by older (”prehistoric”) firewall formats. Fortunately, computer pros learn from their errors, and the firewall technology continues improving daily.

Cisco Kits is a leading provider of CCNA, CCIE and CCNP Cisco training courses and equipment. Visit online for more information on certification or just furthering education.

Article Source:http://www.articlesbase.com/networks-articles/why-firewall-security-is-necessary-to-protect-your-network-784872.html

Transmission Control Protocol (TCP)

 Today, the majority of application protocols use the Internet’s reliable Transmission Control Protocol (TCP). The functionality of TCP  is designed to be adequate not only for Internet applications but also for the variety of underlying networks.

           The protocol aims at providing a reliable service with the following features:

       1. Fairness to other flows that potentially share a channel’s bandwidth

       2. Dynamic discovery of current availability of bandwidth

• 1. Mechanisms for congestion avoidance and control and for optimization of  the error recovery process.

   Error control mechanisms are the central component of reliable protocols. They affect a protocol’s performance with respect to goodput, energy expenditure, and overhead. Error control is usually a two-step process: error detection, followed by error recovery . TCP assumes a relatively reliable underlying network where most packet losses are due to congestion . TCP  error control is centered on congestion losses and ignores the possibility of transient random errors or temporary blackouts due to handoffs and extended burst errors that are typical in wireless networks. TCP detects errors by monitoring the sequence of data segments acknowledged (received). When timeouts are correctly configured, a missing segment is taken to indicate an error, namely that the segment is lost due to congestion (i.e. buffer overflow). Reliable protocols usually implement an error recovery strategy based on two techniques: retransmission of lost segments; and downward adjustment of the sender’s window size and readjustment of the timeout period. When using TCP over wireless links results in congestion control measure being invoked at the source.

            The Additive Increase Multiplicative Decrease (AIMD) algorithm is used to implement TCP window adjustments; based on the analysis the algorithm achieves stability and converges to fairness in situations where the demand (of competing flows) exceeds the channel’s bandwidth .

            In a wireless network, however packet looses will occur more often due to unreliable wireless links than due to congestion. It is shown that the performance of TCP is sensitive to the packet size, and that significant performance improvements are obtained if a ‘good’ packet size is used. Packets on the internet may get lost either due to congestion, or due to corruption by the underlying physical medium. Given the low error rates of wired links, almost all losses are related to congestion. TCP’s reaction to looses is based on this very observation. Losses are detected either by timeouts at the source or by multiple duplicate acknowledgements ( dupacks ) from the receiver. TCP assumes that each packet loss is solely due to congestion. However, in a wireless network, TCP will encounter packet looses that may be unrelated to congestion. Nonetheless, these losses trigger congestion control measures at the source and severely degrade performance.   

TCP was designed and carefully calibrated to overcome the problems like as follows:

• 1. Stability.
• 2. Heterogeneous ( receiver buffers, network bandwidth and delay ).
• 3. Fairness in bandwidth consumption of competing flows.
• 4. Efficiency in utilization.
• 5. Congestion control ( that effectively avoids situations of congestive collapse ).

            Transmission Control Protocol (TCP) is a means for building a reliable communications stream on top of the unreliable packet Internet Protocol (IP). TCP is the protocol that supports nearly all Internet applications. The combination of TCP and IP is referred to as TCP/IP and many people imagine, incorrectly, that TCP/IP is a single protocol.

Performance Metrics of TCP  :

Goodput :

 This is the measure of how efficiently a connection utilizes the network. It is determined as the ratio of useful data received at the destination and the total amount of data transmitted by the source. If a connection requires a lot of extra packets to traverse the network due to retransmission, its goodput is low. It is desirable that each connection have as high a goodput as possible. Clearly, this metric is of great significance for efficient operation of a network.

Throughput :

 This is the measure of how soon an end user is able to receive data. It is determined as the ratio of the total data received by the end user and the connection time. A higher throughput will directly impact the user’s perception of the quality of service.

Article Source:http://www.articlesbase.com/networks-articles/transmission-control-protocol-tcp-789291.html

ISO IEC 27001 International Standard covers all types of organizations (e.g. commercial enterprises, government agencies, non-profit organizations). This International Standard specifies the requirements for establishing, implementing, operating, monitoring, reviewing, maintaining and improving a documented ISMS within the context of the organization’s overall business risks. It specifies requirements for the implementation of security controls customized to the needs of individual organizations or parts thereof. The ISMS is designed to ensure the selection of adequate and proportionate security controls that protect information assets and give confidence to interested parties.

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This ISO 27001 International Standard covers all types of organizations (e.g. commercial enterprises, government agencies, non-profit organizations). This International Standard specifies the requirements for establishing, implementing, operating, monitoring, reviewing, maintaining and improving a documented ISMS within the context of the organization’s overall business risks. It specifies requirements for the implementation of security controls customized to the needs of individual organizations or parts thereof.

The ISMS is designed to ensure the selection of adequate and proportionate security controls that protect information assets and give confidence to interested parties.

NOTE 1: References to ‘business’ in this International Standard should be interpreted broadly to mean those activities that are core to the purposes for the organization’s existence.

NOTE 2: ISO/IEC 17799 provides implementation guidance that can be used when designing controls.

The requirements set out in this International Standard are generic and are intended to be applicable to all organizations, regardless of type, size and nature. Excluding any of the requirements specified in Clauses 4, 5, 6, 7, and 8 is not acceptable when an organization claims conformity to this International Standard.

Any exclusion of controls found to be necessary to satisfy the risk acceptance criteria needs to be justified and evidence needs to be provided that the associated risks have been accepted by accountable persons. Where any controls are excluded, claims of conformity to this International Standard are not acceptable unless such exclusions do not affect the organization’s ability, and/or responsibility, to provide information security that meets the security requirements determined by risk assessment and applicable legal or regulatory requirements.

NOTE: If an organization already has an operative business process management system (e.g. in relation with ISO 9001 or ISO 14001), it is preferable in most cases to satisfy the requirements of this International Standard within this existing management system.

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Article Source:http://www.articlesbase.com/security-articles/deltaprima-konsultan-manajemen-keamanan-informasi-it-security-iso-27000-iso-27001-consultant-business-continuity-bcp-drp-disaster-recovery-787059.html

Don’t overlook your employees’ rejection of your security policies. Without their understanding and acceptance, your company’s information security is at stake.

Here is a very good article why we should and how we can enforce security policies in a corporate environment:

http://www.cw.com.hk/article.php?type=article&id_article=2588

As we have discussed before in this blog, the point is that you need to let employees know why there are security policies and how the policies are benefiting them. And let them know the consequences of violating the policies.

CISCO has recently released a study that shows many employees do not follow Security Policies in the work environment. The reason is that they think the policy is not fair to them, and that the policy is not aligned with the reality of their daily work activities.

http://www.cw.com.hk/article.php?type=article&id_article=2591

In the article, it states:
“The study found that the majority of employees believe their companies’ IT security policies are unfair. Indeed, surveyed employees said the top reason for non-compliance is the belief that policies do not align with the reality of what they need to do their jobs, according to Cisco”.

This reconfirms that the human factor in Information Security is still the primary issue we need to deal with in our day-to-day security management.

Tags: Information Security Policy, Information Security Policy Management, Employee Attitude to Security Policy, Security Policy, Security Policy Management

For every first lesson I teach about Risk Management and Contingency Planning, I always like to raise an example to begin a discussion about the illusions of human beings.

This illusion is best illustrated by an interesting game called the Monty Hall Problem, which goes like this:

Suppose you are a lucky game show player who is picked to participate in a game. The game requires you to stand in front of the three doors. Behind one door is a car, and behind each of the other two doors is a goat. You are told to choose one of the doors, and if you choose the door to the car, you win the car.

The game requires you to make your choice, and then the host (who knows what is behind each door) will open one of the other two doors that he knows does not open to the car. According to the game rules, you have the chance to change your mind and choose the other remaining door, or remaining with your original choice.

The problem is: Should you pick the other remaining door, or trust your first choice? Would this decision make any difference in the chance of winning the car?

Most people will say that the chance is the same for whichever choice because you have half the chance to win the car out of the two remaining doors. It sounds logical, doesn’t it?

But let’s examine this carefully. Suppose you label these two strategies as:

Strategy A:  Remaining with the present door choice.

Strategy B:  Changing the choice to pick the other remaining door.

Let’s take a look at Strategy A first, where there are two outcomes:

Strategy A, Outcome 1: Your original door choice was the one if front of the car all along, and you win because you chose to remain with the first door you picked. The chance of you picking the door with the car at the beginning of the game was 1/3 because you had to choose one out of the three doors.

Strategy A, Outcome 2: Your original door choice was one of the two doors in front of a goat, and you lose because you chose to remain with this first door you picked.  There is 2/3 of chance for this scenario to take place, since two of the doors had goats behind them.

So for Strategy A, you had only a 1/3 chance to win the car.
What about Strategy B, where you change your original choice?

Strategy B, Outcome 1:  You change your door choice, and unfortunately your new door choice is hiding the other goat. You lose. Remember you have 1/3 of chance in this outcome as discussed previously.

Strategy B, Outcome 2: You change your door choice, and open the door hiding the car. You win! And you have 2/3 of chance in this outcome. (If you’re interested in a full explanation of how the outcome changes to 2/3, search for the term “Monty Hall Problem” using your favorite search engine and you’ll find plenty of information.)

Looking at the problem this way, it’s quite obvious that Strategy B is a better choice, isn’t it?

Some of you might still feel confused. You might need to re-read the whole discussion above to clarify your thoughts.

Ultimately, this game illustrates one very important weakness of people: We tend to jump to conclusions for many problems too easily without careful analysis. And worst of all, we are usually over confident as to what we have concluded at the beginning.

This problem is closely related to the people issue in Information Security or Corporate Risk Management. People tend to overlook many possible system vulnerabilities when undergoing so-called “risk analysis”. They are not aware that they have been overly naïve when thinking about the possible threats to their system of operations.

It’s quite interesting that this phenomenon is well observed now, as there are so many financial institutions around the world running into their own financial problems because the people who run those organizations were too confident in themselves to manage the risks. And indeed, they seem to be completely blind to the possible exposure of managing and holding all those financial products they have on hand, without even thinking about the possible serious consequence of dragging down their own companies if things go against them. And indeed, it catches up to them in the end.

So in the risk management exercise of information security, the number one beneficial attitude is to be humble. We need to realize that we are not invincible, and be very careful in weighing all possible risks related to the information system we are using. We have to work out the plan in every step of risk management without the tendency to overlook or jump to conclusions too easily. Without the right mind set, we are very likely to fail to manage all possible risks properly.

Tags: Corporate Governance, IT Governance

For most S/MIME compatible email clients, you must obtain a PKCS12 format certificate before you can upload your private key and/or others’ public key for secure email communication.

The first way you can do this is, of course, to apply such a certificate from a trusted Certificate Authority (CA), such as VeriSign. But can you do this without a CA?

Yes, it is possible for you to generate such a certificate manually using open source software. However, note that the certificate is self-signed, meaning it is signed by you as the trusted root source.

To do this, you have first to download a piece of software than can generate PCKS12 format certificates. The most common one is OpenSSL software.  You can visit this website to know more:

http://www.openssl.org.

The original OpenSSL software is made primarily to be run on the Linux platform. As a general Windows user, you might need to use the program on a Windows platform, and may not know how to compile the source code of OpenSSL to make it run on a Windows platform. If you have this headache, you can try the Windows compatible OpenSSL work available for free here:

http://www.slproweb.com/products/Win32OpenSSL.html

Upon successful installation of the software, go to the bin directory of your installation to locate the software openssl.exe that you need to use to generate PKCS12 certificate.

I followed the instructions here to create my own certificate:

http://tinyurl.com/4s5zqo

I have added my own explanations and remarks and simplified a bit the process. Here are the steps:

Assume you have installed your software on the path c:\Openssl

1.    Generate a RSA Private Key in PEM format

Type:
>C:\Openssl\bin\openssl.exe genrsa -out my_key.key 2048
Where:

• my_key.key  is the desired filename for the private key file
• 2048  is the desired key length of either 1024, 2048, or 4096

2.    Generate a Certificate Signing Request:
Type:
>C:\Openssl\bin\openssl.exe req –new –key my_key.key –out my_request.csr

• my_key.key is the input filename of the previously generated private key
• my_request.csr  is the output filename of the certificate signing request

3.    Follow the on-screen prompts for the required certificate request information.
4.    Generate a self-signed public certificate based on the request.
Type:
>C:\Openssl\bin\openssl.exe x509 -req -days 3650 -in my_request.csr -signkey my_key.key -out my_cert.crt

my_request.csr  is the input filename of the certificate signing request
my_key.key is the input filename of the previously generated private key
my_cert.crt  is the output filename of the public certificate
3650 are the duration of validity of the certificate. In this case, it is 10 years (10 x 365 days)
x509 is the X.509 Certificate Standard that we normally use in S/MIME communication

This essentially signs your own public certificate with your own private key. In this process, you are now acting as the CA yourself!
5.    Generate a PKCS#12 file:
type:
>C:\Openssl\bin\openssl.exe pkcs12 -keypbe PBE-SHA1-3DES -certpbe PBE-SHA1-3DES -export -in my_cert.crt -inkey my_key.key -out my_pkcs12.pfx -name “my-name”

• my_cert.crt  is the input filename of the public certificate, in PEM format
• my_key.key  is the input filename of the private key
• my_pkcs12.pfx  is the output filename of the pkcs#12 format file
• my-name  is the desired name that will sometimes be displayed in user interfaces.

6.    (Optional) You can delete the certificate signing request (.csr) file and the private key (.key) file.
7.    Now you can import your PKCS#12 file to your favorite email client, such as Microsoft Outlook or Thunderbird. You can now sign an email you send out using your own generated private key. For the public certificate (.crt) file, you can send this to others when requesting them to send an encrypted message to you.

Tags: self-signed Public Key, OpenSSL command

Can we use self generated Public and Private Keys to communicate without Public Key Infrastructure?

Originally, you can use PGP (Pretty Good Privacy) freeware to communicate freely. PGP freeware can be downloaded here:

http://www.pgpi.org/products/pgp/versions/freeware/

However, since they have recently taken down the freeware for the Windows platform, I’ll show you how to use another piece of software called “gpg4win” to do the same thing.

This software was created from an open source effort, and it supports OpenPGP standard. With a suitable plugin, you can use this with some other email clients such as Thunderbird and Clawmail for S/MIME email encryption.

You can download the latest version here:

http://www.gpg4win.org

Upon successful installation, you’ll find the following welcome screen:

Select “Generate key now” if you do not have a PGP private and public key pair.

Input your full name and email address, then carefully input a passphrase. This is an important step, so select something you can recall because you need to correctly enter your passphrase when you want to use your private key later.

Follow the onscreen instructions and create your key pairs. If you require a backup key to be generated, make sure you save the key pair in a safe place.

Now you can see your newly generated key in the application windows like the one I have generated for myself:

Public Key Infrastructure: Using GPG4WIN

However, before you ask someone to send an encrypted message to you, you need to export your public key to them. You can select the “Export” function of the application window to do this.

After selecting the Export function, the program will ask you where to save the exported public key. Select a location where you can retrieve the saved public key later.

Now you can send your key to anyone who needs to send you confidential messages. Those who have your public key can then encrypt the message using your public key. Those encrypted messages can only be opened by you, who owns the private key.

As an example, suppose there is someone who already has encrypted a message (or simply a file) using your public key. Let’s call the original file “plaintext.doc,” and the encrypted file you received should be “plaintext.doc.gpg”. (The software adds the file extension “.gpg” to the output file it has encrypted)

Pressing the “Files” button under the application window displays the program’s file manager. You can locate and select the file “plaintext.doc.gpg” that has been saved in your computer previously.

GPG4WIN File Manager

By pressing the Decrypt button, you are prompted to enter the passphrase for your private key to decode the file. Upon presenting the correct key, you should now have the decrypted file under the same directory of your encrypted file.

To encrypt any file to other people, you need to import their public key by using the Import function of the main application screen. Select the public key file you obtain from other people (this should be a file with file extension “asc”), and click okay to proceed with the import.

By using the same file manager, you can select the file you want to encrypt and then choose the “Encrypt” function to produce the encrypted output file. Remember to use the public key of the person you have just imported to encrypt the file. You can then send this file to the party who owns the private key of the corresponding public key you have just imported to encrypt the file. That party should be able to decrypt the file using his/her private key.

Try this software and let me know if you have any problems or issues by leaving a message here.

Tags: GNU Privacy Assistant

I read a piece of news about the security issue of the new Google Browser Chrome from ComputerWorld.

The Google Browser is an open source project, and many of the components it was built on use open source software. One of them is the open-source rendering software called WebKit. This component was found to have a security flaw in its older version. It allows the attacker to maliciously trick web surfers into downloading a java (or other types of) executable file from a webpage. As the downloaded file appears, a button under the Chrome browser could be pressed by the user and hence run the program.

Since a java executable file will not warn the user before it runs, the user could accidentally trigger a malicious java program.

For details of this news, refer to this article:
http://www.cw.com.hk/article.php?id_article=2236

This security flaw has been identified previously with Safari, the browser from Apple. Apple patched the flaw last June.

To avoid the possible download of a malicious file, you can turn on the option to prompt the user for the file download path under Options → Minor Tweaks → Ask where to save each file before downloading.

In fact, other than this security issue, I always recommend using browsers under open source efforts such as Firefox, or now Chrome, because those browsers are built using program sources that are open to everyone. Then, security experts can always look at the program code details inside the program to uncover potential security flaws. This makes the software safer to use in the long run.

Tags: Google Chrome, Apple Safari, Google Chrome Security Issue, Google New Browser

This article will tell you about a simple way to check whether your computer system has a trojan horse (spyware) implemented.

A trojan horse or spyware operates by running on your computer and opening a communication port (TCP port) to communicate with the remote hacker, so he or she can “spy” on your computer. The easiest way to detect this activity is to look at the ports opened on your computer by using the built-in DOS function netstat. At the DOS prompt, type this command with the switch “-a”, (i.e. “netstat -a”) to look for the ports opened on your computer.

If you have no idea what ports are usually related to a trojan horse, you can do a search on any search engine for the term “common trojan horse ports”. Here are two of the reference sites I’ve found:

http://www.doshelp.com/Ports/Trojan_Ports.htm

http://personal.telefonica.terra.es/web/oscarmartinez/_articlesan/article49-Trojan-horse-ports.htm

If you still have a hard time decoding the lists from these reference sites, you can use a handy program called “fport”. Download this here:

http://www.foundstone.com/us/resources/proddesc/fport.htm

This program helps match your opening ports with the programs in your computer. This is easier way to locate a particular suspicious program in your computer to uncover any potential spyware residing on your computer.

Please note that since this is a command mode program, you need to bring up a command prompt window by choosing Start ==> Run and then type in the command “cmd” in the “Run” window. Next, type in the exact path of the program. For example, if you have installed the program under c:\, type in c:\fport to run it. The program will create a list of programs associated with your computer under inspection. If you have difficulty comprehending a long list of ports on the command prompt window, you can tell the program to redirect the outputs to a text file for printing and later analysis. You can do this by typing, for instance, “c:\fport > c:\output.txt” to create a file named “output.txt” on your c:\ drive.

This is a handy tool for running an inspection on your computer to detect any possible hacker’s attack. I recommend that you use it regularly – it’s to your benefit.

Tags: Trojan Horse Removal, Popular Trojan Horse Port List

Let’s begin by looking at the meaning of the word “policy”. Walt, C. (2001a) defines a policy in practical security terms as “a published document (or set of documents) in which the organization’s philosophy, strategy, policies, and practices with regard to confidentiality, integrity and availability of information.”

In other words, it’s actually management’s intention for how various stakeholders, especially employees, should uphold and follow the required security standards in operating the company’s activities.

Policies should:

• state reasons why the policy is needed
• describe what is covered by the policy – whom, what, and where
• define contacts and responsibilities to outside agencies
• discuss how violations will be handled

A recent journal by James and Coldwell (2007) states that corporate policies should consider security and ethics issues. Management should include explicit statements about the following:

• An organization’s method of handling the security of its system and information;
• Privacy and security issues of information;
• Informational assets complying with the impact of ethical behavior and conflict.

Users should be educated to recognize the value of assets, risks, and costs of compromise, as the human being is always the weakest link in security management. Therefore, when designing a security policy, human factors should be closely examined and reviewed. This view is supported by a white paper from British Telecommunication plc (BT White Paper 2004).

If you take a look at most security life cycle models, you will notice that a security policy is at the center of security processes, as shown in some typical models below:

http://www.sans.org/reading_room/whitepapers/testing/260.php (SANS Institute)

http://www.bradreese.com/andrew-r-reese.htm (BradReese.com)

http://www.audisec.com/html/philosophy.html

You should not overlook this important security tool in your organization n, should you?

Reference:

BT Write Paper (2004), ‘Why Security Policies Fail’, http://www.mis.uwec.edu/keys/Teaching/is365/208770-BT%20Why%20Security%20Policies%20Fail%20-20000718.pdf Accessed 08/08/08

James, H. and Coldwell, R.A. (1993), ‘Corporate Security: An Australian Ostrich’, Information Management & Computer Security, Vol 1, (Issue 4), 10-12

Walt, C. (2001a), ‘Introduction to Security Policies, Part One: An Overview of Policies’, SecurityFocus, August 27, 2001, http://www.securityfocus.com/print/infocus/1193 Accessed 08/08/08

Walt, C. (2001b), ‘Introduction to Security Policies, Part Three: Structuring Security Policies’, SecurityFocus, October 9, 2001, http://www.securityfocus.com/infocus/1487 Accessed 08/08/08

Weil, S. (2004), ‘How UTIL Can Improve Information Security’, December 22, http://www.securityfocus.com/infocus/1815 Accessed 08/08/08

Tags: Security Life Cycle Model