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ACL by niusheng11



Short for Access Control List, ACL is a listing that tells a computer operating system
or other network device what rights a users has to each item on a computer or
network device.


Authentication and authorize are terms used to describe the process of identifying
a person and making sure they are really who they say they are. For example, a
password is a very basic method of authorizing someone.

Antivirus program

Also known as Antivirus Software, AVS, or just AV; an antivirus program is a type of
software is designed to protect your computer and/or network against computer
viruses. If and when a virus is detected, the computer will generally prompt you
that a virus has been found, and ask what action should be done such as deleting
the virus.

Asymmetric Encryption

A type of encryption where the key to encrypt and decrypt the information is
different. This type of encryption gives the encryption even more security by
preventing someone from creating a decryption key from the encryption key used
to encrypt the data.


An organized attempt on a person or company designed to cause issues or damage.
For example, a DOS attack is designed to cause a decrease of performance or
completely take down a web site.


Also known as a manhole or trapdoor, a backdoor is a term used to describe a back
way, hidden method, or other type of method of bypassing normal security in order
to obtain access to a secure area.

Boot sector virus

Type of computer virus that infects the first or first few sectors of a computer hard
drive or diskette drive allowing the virus to activate as the drive or diskette boots.

Brute-force attack

A type of password attack that does not attempt to decrypt any information but
simply continue to try different passwords. For example, a brute-force attack may

have a dictionary of all words and/or a listing of commonly used passwords. To gain
access to the account using a brute-force attack, the program would try all the
available words it has to gain access to the account. Another type of brute-force
attack is a program that runs through all letters and/or letters and numbers until it
gets a match.

Although a brute-force attack may be able to gain access to an account eventually,
these types of attacks can take several hours, days, months, and even years to run.
The amount of time it takes to complete these attacks is dependent on how
complicated the password is.

To help prevent brute-force attacks many systems will only allow a user to make a
mistake in entering their username or password three or four times. If the user
exceeds these attempts the system will either lock them out of the system or
prevent any future attempts for a set amount of time.


   1. Algorithm of encoding or encrypting data. Text that is ciphered is text that
      cannot be read unless a special password or key is put in to decode it.
   2. Windows command line command. See cipher command page for additional
      details and examples.


Term used to describe data that is kept from any other users that should not have
access to it unless permission is granted by the owner of the data.


Individual who is able to decipher codes and passwords being able to break security
systems for illegal reasons.


The process of manipulating data so that is unreadable and also being able to
reverse this process. This is usually used for security reasons for important files so
that it can be seen only by people that are supposed to see it.


The study of cryptography.

Data theft

Term used to describe when information is illegally copied or taken from a business
or other individual. Commonly, this type of information is user information such as
passwords, social security numbers, credit card information, other personal
information, and/or other confidential corporate information. Because this
information is illegally obtained, when the individual who stole this information is
apprehended, it is likely he or she will be prosecuted to the fullest extent of the



Short for Distributed Denial of Service, DDoS is a type of DoS attack that uses
several computers to attack one victim. Often a DDoS attack is first done by
hacking or infecting dozens, hundreds, or even thousands of other computers with
instructions on when to attack and how; when that time arises, all infected
computers attack at once. A DDoS is often needed to attack a big site that is
capable of handling large ammounts of traffic.


Process of taking encoded or encrypted text or other data and converting it back
into text that you or the computer are able to read and understand. This term
could be used to describe a method of un-encrypting the data manually or with un-
encrypting the data using the proper codes or keys.

Default password

A password (usually "admin", "root", "password", "<blank>", "secret", or "access")
assigned to a program or hardware device by the developer or manufacturer.
Although default passwords may help protect from some users they can be easily
entered by users that know what they are doing.


The first Public Key Cryptography developed by Whitfield Deffie and Martin
Hellman in 1976.


      1. Short for Disk Operating System, DOS is an acronym often used to describe
      2. Short for Disk Operating System, DOS refers to any type of operating system
         that runs from a disk drive. Today all operating systems could be considered
         disk operating systems.
      3. Short for Denial of Service, a DoS attack is a form of attacking another
         computer or company by sending millions or more requests every second
         causing the network to slow down, cause errors or shut down. Because it is
         difficult for a single individual to generate a DoS attack, these forms of
         attacks are often created from another company or college and/or worms
         are created to create zombie computers to create a DoS attack.


Short for Data Encryption Standard, DES is also sometimes referred to as the Data
Encryption Algorithm (DEA) and is a type of encryption standard first approved as a
US federal standard in November 1976. Although still sometimes used, DES has
been widely replaced by AES.

Dictionary attack

A type of password attack that does not attempt to decrypt any information but
simply tries each of the words in a dictionary in hopes that the user has used one of
the words as his or her password.

To help prevent brute-force attacks many systems will only allow a user to make a
mistake in entering their username or password three or four times. If the user
exceeds these attempts the system will either lock them out of the system or
prevent any future attempts for a set amount of time.

Digital signature

Method of data encryption used to verify the identity of an individual transmitting
information over the Internet.

Digital Certificates
 Digital certificates are electronic documents used to verify the unique identities
 of principals and entities over networks such as the Internet. A digital
 certificate securely binds the identity of a user or entity, as verified by a
 trusted third party known as a certificate authority, to a particular public key.
 The combination of the public key and the private key provides a unique
 identity to the owner of the digital certificate.

DNS hijacking

Unauthorized and illegal modification of a DNS server that directs users attempting
to access a web page to a different web page that looks the same, a competitor
page, or a page insulting the company or organization owning the real page.

E-mail bomb

Term used to describe a type of attack where a user or group of users send a
massive amount of e-mails to interrupt the user or business from receiving e-mail,
responding to e-mails in a timely fashion, or causing other e-mail related issues.


In general the term spoof refers to a type of hacking or deception technique that
imitates another person, software program, hardware device, or computer, with
the intentions of bypassing security measures. One of the most commonly known
types of spoofing is IP spoofing.


Also known as earwigging, eavesdropping is a term used to describe the process of
listening, monitoring, and/or examining someone without their permission and/or
knowledge. For example, a user could eavesdrop on someone's e-mail or chat


The process of making data unreadable by other humans and/or computers for the
purpose of preventing others from gaining access to its contents. Encrypted data is
generated using an encryption program such as PGP, encryption machine, or a
simple encryption key and appears as garbage until it is decrypted. In order to read
or use the data, it must be decrypted and only those who have the correct
password and/or decryption key are able to make the data readable again.

A very basic encryption technique known as simple substitution or a substitution
cipher shifts the letters of the alphabet over a few characters. For example, as
shown below the alphabet has been shifted over four characters.

Encrypt key:
a=e, b=f, c=g, d=h, e=i, f=j, g=k, h=l, i=m, j=n, k=o, l=p, m=q, n=r, o=s, p=t, q=u,
r=v, s=w, t=x, u=y, v=z, w=a, x=b, y=c and z=d.

Decrypt key:
a=w, b=x, c=y, d=z, e=a, f=b, g=c, h=d, i=e, j=f, k=g, l=h, m=i, n=j, o=k, p=l, q=m,
r=n, s=o, t=p, u=q, v=r, w=s, x=t, y=u and z=v

Using this technique a user could encrypt the message: "computer hope free help
for everyone" to: "gsqtyxiv lsti jvii lipt jsv izivcsri". Below is an example of how this
could be done using Perl.

       $alpha = "abcdefghijklmnopqrstuvwxyz";
       $message = "computer hope free help for everyone";

       @alpha = split(//, $alpha);

       foreach $alpha (@alpha) {
       if ($i >= 23) {
       $i = -3;
       $key{$alpha} = $alpha[$i+3];

       @message = split(//,$message);

       foreach $message (@message) {
       if ($message =~/[a-z]/i) {
       $new .= "$key{$message}";
       else {
       $new .= "$message";

       print "Old: $message\nEncrypted: $new\n";

Ethical hacking

A term used to describe a type of hacking that is done to help a company or
individual identify potential threats on the computer and/or network. In order for
hacking to be deemed ethical the hacker must obey the below rules.

   1. You have permission to probe the network and attempt to identify potential
      security risks. It's recommended that if you are the person performing the
      tests that you get written consent.
   2. You respect the individual's and/or company's privacy and only go looking
      for security issues.
   3. You report all security vulnerabilities you detect to the company, not
      leaving anything open for you or someone else to come in at a later time.
   4. You let the software developer or hardware manufacturer know of any
      security vulnerabilities you locate in their software or hardware if not
      already known by the company.

Users who are interested in becoming a Certified Ethical Hacker (CEH) can visit

File protection

Methods used in protecting valuable data on computers. Generally, file protection
is accomplished by password protecting a file or only providing rights to a specific
user or group.


A software utility and/or hardware device that
limits outside network access to a computer or
local network by blocking or restricting ports.
Firewalls are a great step for helping prevent un-
authorized access to a company or home network.
The image to the right is a 3Com SuperStack 3
Firewall, an example of what a hardware firewall
may look like.

      A listing of computer firewall programs as well as additional information
       about preventing unauthorized access to your computer can be found on
       document CH000464.
      See document CH000907 for additional information about disabling
      Additional information about computer security can be found on our
       security question and answer page.


   1. Also known as an admin, administrator, and gatekeeper, root is a super user
      on a computer network. Generally, a root is used to refer to the system
      administrator on a Unix / Linux network and is an individual who has
      complete access to a network.
   2. The highest level in a directory hierarchy. For example, in MS-DOS, the root
      of the primary hard disk drive would C:\.

        See our su or super user command page for additional information on this
         command and/or visit our Unix / Linux help page for a full listing of
         commands and help.
        Additional information and help with MS-DOS can be found on our MS-DOS
         help page.
        Users in the Microsoft recovery console can set the current directory to the
         system root directory by using the systemroot command.


1. A term that first started being used in the 1960s and was used to describe a
programmer or someone who hacked out computer code, later the term evolved to
an individual who had an advanced understanding of computers, networking,
programming, and/or hardware but did not have any malicious intents.

Today, a hacker is often associated with an individual who illegally breaks into
other computer systems to damage and/or steal information. Some users today
who consider themselves leet may refer to themselves as haxors or h4x0rs.
However, often these types of users are nothing more than script kiddies.

Although the media and most people think of hackers as malicious or evil, the
majority of hackers are people who are curious about how computer, networks,
and/or programs work and are often simply exploring and learning.

2. In computer online gaming a hacker is a term often associated with a gamer who
is cheating.

        Additional information about how to hack someone or something can be
         found on document CH000806.
        For information about where Computer Hope stands on hackers, please see
         our underground section.

Identity theft

A description of a type of data theft where the person obtaining the information
illegally is primarily searching for personal information and/or records. Often the
user is looking for such information as full name, maiden name, address, date of
birth, social security number, passwords, phone numbers, email, family
information, credit card numbers, other credit information, etc. The user then uses
this information to gain access to bank accounts or other protected areas, uses
your personal information as their own identification, and/or sells your

Tips on preventing identity theft:

   1. When entering any personal information on the Internet make sure you're
      entering it on a secure page. Additional information about making sure an
      Internet page is secure can be found on document CH000507.
   2. When purchasing something over the Internet unless you plan on buying
      something from that same company again in the near future do not store
      your credit card and/or personal information with that site.

      3. Make sure to have an active and up-to-date spyware protection program and
         antivirus protection program.
      4. Be aware of fake e-mails / phishing e-mails that claim to be a company such
         as your bank requesting any personal information or login information.
      5. Make sure your computer is secure. Additional information and tips on
         securing your computer can be found on document CH000464.
      6. If you're a victim of a stolen computer make sure to read document
         CH001011 for additional information and help with dealing with this issue.

          Additional information and help with identity theft can also be found at:


Short for Intrusion Detection System, IDS is a security measure that helps notify an
administrator or company when a device is being opened. For example, some
corporate computers are equipped with an IDS system; if the case is removed from
the computer an alarm will sound.


In general the term spoof refers to a type of hacking or deception technique that
imitates another person, software program, hardware device, or computer, with
the intentions of bypassing security measures. One of the most commonly known
types of spoofing is IP spoofing.

IP spoofing

          A method of bypassing security measures on a network or a method of
          gaining access to a network by imitating a different IP address. Some security
          systems have a method of helping to identifying a user by his or her IP
          address or IP address range. If the attacker spoofs their IP address to match
          this criteria it may help bypass security measures. This technique is also
          used to deceive a web page, poll, or other Internet contest into thinking the
          user is someone else allowing him or her to get more hits or falsely increase
          a votes rank.

E-mail or address spoofing

          Process of faking a senders e-mail address. This type of spoofing is used to
          fool the recipient of the e-mail into thinking someone else actually sent them
          the message. This is commonly used to bypass spam filters or to trick the
          user into thinking the e-mail is safe when in reality it contains an attachment
          that is infected with a virus.

Web page spoof

          A fake web page or spoof on another commonly visited page. For example a
          malicious user may create a spoof page of Microsoft's, eBay, PayPal or
          Google's home page that looks identical but is hosted on a different server.
          These type of pages are commonly used in phishing e-mails to extract
          information from the user such as usernames and passwords or to send

        malicious files to them.


Developed by MIT, Kerberos is network authentication protocol designed to encrypt
and secure data on an insecure network.

See the official MIT Kerberos page at:

Logic bomb

An error in the logic of a software program routine that results in the destruction
of the data. Unlike a virus, logic bombs do their damage right away, then stop.
Also, logic bombs are unintentional and can be the result of a simple corrupt file.


To login or logon is the process users must complete to gain control to a computer,
network, bulletin board or other service that requires authorization. Most logins
require that the user enter his or her username and password.

If you're looking for the location to log into the Computer Hope forums it can be
found here.

Macro virus

A MAC or Macro virus is a type of computer virus that spreads to other computers
through software programs that utilize macros. For example, Microsoft Word and
Microsoft Excel are two popular and widely used programs that are capable of
executing macros. Macro viruses written for these programs can quickly spread by
infecting other related documents each time the document is open. Because these
types of files are commonly used and sent through e-mail, a computer network can
be quickly infected by these viruses.

Man-in-the-middle attack

A type of attack where a user gets between the sender and receiver of information
and sniffs any information being sent. In some cases, users may be sending
unencrypted data, which means the man-in-the-middle can easily obtain any
unencrypted information. In other cases, a user may be able to obtain the
information from the attack but have to unencrypt the information before it can be


   1. A term used to describe when new information or data replaces old
      information or data.
   2. One of two typing settings on a keyboard, overwrite mode allows new input
      to replace existing characters. The Insert keyboard key is commonly used to
      toggle this mode, enabling or disabling it.
   3. When referring to a virus, an overwrite virus is a type of computer virus
      that overwrites a file with its own code, helping spread the virus to other

        files and computers.


Sometimes abbreviated as PWD (not to be confused with the pwd command), a
password is a set of secret characters or words utilized to gain access to a
computer, network resource, or data. Passwords help ensure that computers
and/or data can only be accessed by those who have been granted the right to
view or access them.

Strong password - Term used to describe a password that is an effective password
that would be difficult to break. Often a strong password has between six and ten
characters, numbers and other characters, and upper and lowercase.

Weak password - A password that is not an effective password because it's easy to
remember. Examples of a weak password are names, birth dates, phone numbers,

       See Computer Hope document CH000300 for additional information about
        computer passwords as well as tips for how you should set your computer
        password to help prevent it from being guessed.
       See document CH000767 for additional information about changing your
        username and/or password.
       See our security questions and answer section for a listing of other password
        and security related questions.


Piece of software code that can be applied after the software program has been
installed to correct an issue with that program. Most software programs may have
several patches released after the initial release and commonly update the version
of the program when successfully installed.

Software patches can be found through the software developer's web site. If you're
looking for a patch for your software program, we suggest you visit our third-party
contact page for a comprehensive listing of all computer related companies and
their Internet addresses to obtain your patch.


Term used to describe the instructions a virus or worm executes in addition to
copying itself when infected on the computer. For example, a payload of a
computer virus may be to delete some or all of the files on the computer.


Also known as rights, permissions are characteristics given by users or network
administrators on a network that prevent or allow access to files on a computer
network. Below are examples of rights that may be available to be assigned or

All - All rights granted.
Execute - The right to execute a file or a file within that directory.
Read - The right to read a file.
Write - The right to write to a file.

Often these above rights can be assigned or removed to a single user or a group of

       If you wish to see the attributes in MS-DOS use the attrib command.
       If you wish to see the ACLs or permissions in MS-DOS use the cacls
       If you wish to see the permissions in Linux / Unix use the chmod command.


Short for Pretty Good Privacy, PGP was freeware released in 1991 by Philip
Zimmermann, PGP is a public-key authentication and encryption method based on
the IDEA single-key and RSA public-key encryption algorithms. PGP is now a product
of PGP Corporation and still widely used encryption tool.

Non-commercial United States citizens can also freely obtain PGP from various web
sites. MIT has a great page containing PGP for various platforms, see the MIT
distribution site for PGP for downloads.


Pronounced like fishing, phishing is a term used to describe a malicious individual
or group of individuals scamming users by sending e-mails or creating web pages
that are designed to collect an individual's bank or credit information. Below is an
example of what a phishing e-mail may look like.

       eBay request: Your Account Has Been Suspended!

       Dear eBay customer,

       Your Account has been Suspended. We will ask for your password only
       once.We will charge your account once per year. However you will receive a
       confirmation request in about 24 hours after the make complete unsuspend
       process.You have 24 hours from the time you'll receive the e-mail to
       complete this eBay Request.
       Note: Ignoring this message will cause eBay TKO delete your account forever.

       To make unsuspend process please use this link:

       eBay will request personal data(password;and so on) in this email.
       Thank you for using eBay!


       This eBay notice was sent to you based on your eBay account preferences.If
       you would like to review your your notification preferences for other types of
       communications, click here.If you would like to receive this email in text
       only,click here.

To a user who frequently uses eBay or any online service, these e-mails may appear
as if they have come from the company described in the e-mail. However, phishing
e-mails are designed to deceive the user and trick them into visiting the links in
the e-mail that are designed to steal personal information such as usernames,
passwords, credit card information, etc. Below are some helpful tips on identifying
these types of e-mails and how to handle them.

How to identify a phishing e-mail.

   1. Company - These types of e-mails are sent out to thousands of different e-
      mail addresses and often the person sending these e-mails has no idea who
      you are. If you have no affiliation with the company the e-mail address is
      supposedly coming from, it's fake. For example, if the e-mail is coming from
      Wells Fargo bank but you bank at a different bank.
   2. Spelling and grammar - Improper spelling and grammar is almost always a
      dead give away. Look for obvious errors.
   3. No mention of account information - If the company really was sending you
      information regarding errors to your account, they would mention your
      account or username in the e-mail. In the above example the e-mail just
      says "eBay customer", if this really was eBay they would mention your
   4. Deadlines - E-mail requests an immediate response or a specific deadline.
      For example, in the above example, the requirement to log in and change
      your account information within 24 hours.
   5. Links - Although many phishing e-mails are getting better at hiding the true
      URL you are visiting, often these e-mails will list a URL that is not related to
      the company's URL. For example, in our above eBay example: is not an eBay URL, just a URL with a ebay
      section. If you're unfamiliar with how a URL is structured , see our URL
      dictionary definition for additional information.

What to do if you're not sure if an e-mail is official.

       Never follow any links in an e-mail you're uncertain about. Instead of
        following the link in the e-mail, visit the page by manually typing the
        address of the company. For example, in the above example, instead of
        visiting the fake ebay URL, you would type: in your
        web browser and log in through the official web site.
       Never send any personal information through e-mail. If a company is
        requesting you send them personal information about your account or are
        saying your account is invalid, visit the web page and log into the account
        as you normally would.
       Finally, if you are still not sure about the status of your account or are
        concerned about your personal information, contact the company directly,
        either through an e-mail address provided on their web site or over the

Issues phishing e-mails commonly address

Below are some of the issues a phishing e-mail may inquire about in order to trick

      Account issues, such as account or password expiring, account being
       hacked, account out-of-date, or account information needing to be
      Credit card or other personal information, such as credit card expiring or
       being stolen, incorrect social security number or other personal
       information, or duplicate credit card or other personal information
      Confirming orders, such as request that you log in to confirm recent orders
       or transactions.

Common companies affected by phishing

Below is a listing of some of the companies phishers often send e-mails about.

      Any major bank
      Popular web sites such as: Amazon, MySpace, PayPal, eBay, Microsoft,
       Apple, Hotmail, YouTube, etc.
      Government: FBI, CIA, IRS, etc.
      Internet service providers such as: AOL, MSN, etc.
      Casinos and lottery.
      Online dating or community web sites.

      See document CH000464 for additional information about protecting your
       computer from unauthorized access.

Port scanner

A software program designed to go through a large listing of interesting ports or all
available network ports and probe each port to see if it is available or open and
accepting packets. Using a port scanner a user can check for any potential security
vulnerabilities and prevent users from accessing a computer or other network
device through any open ports.

      An example of a port scanner is the *nix nmap command.

Privilege level

The granted access level that a user has been given on a computer network. The
higher the privilege level, the more the user is capable of doing on the computer
and/or network.


The rights, access or other abilities a user or computer has been given to another
computer, network, program, and/or hardware device. For example, a person who
works for a companies customer service department may have the privileges to
view a customers information where other employees who do not need this ability

lack the privileges.

Public Key Cryptography

A type of cryptography that has a public and private key. The public key can be
viewed or used by anyone but the private key is kept secret by the creator and is
the only method of decrypting the data encrypted by the public key.


A system or set of steps that helps keep data from prying eyes by utilizing
passwords, encryption and hiding data. While security does not guarantee that data
cannot be compromised, extra security steps can help in preventing data from
being compromised.


A packet sniffer is a utility that has been used since the original release of
Ethernet. Packet sniffing allows individuals to capture data as it is transmitted over
a network. Packet sniffer programs are commonly used by network professionals to
help diagnose network issues and are also used by malicious users to capture
unencrypted data like passwords and usernames in network traffic. Once this
information is captured, the user can then gain access to the system and/or

If you wish to keep information confidential or are concerned about packet
sniffing, it is advised that you work on encrypted protocols and encrypt all
sensitive data, such as e-mails, being sent over the Internet and/or network. A
great encryption program is PGP, users who are using Telnet should consider using
SSH instead.

Social engineering

Term used to describe the act of tricking a person by the act of deception. For
example, someone attempting to gain unauthorized access to network may call a
business and trick someone into thinking they work for the company and ask for
passwords or other company confidential information so they can gain access to the


   1. Term used to describe a software program that is intentionally installed on
      the computer by a user to monitor or spy on what other users of the same
      computer are doing.
   2. A term used to describe a software program that has been designed to track
      a user's activity without the user fully understanding the intentions of the
      program or not knowing about its installation. Spyware programs are often
      used to help with tracking users' habits and help with delivering proper
      advertisements to a user. Spyware is installed onto a user's machine when
      installing free programs such as free music sharing programs, visiting web
      pages such as adult oriented web pages, and through other downloads and
      plug-ins on the Internet.

       Additional information about Spyware, Malware, and Adware programs
        being installed and/or your browser being hijacked can be found on
        document CH000578.
       Information about how your computer becomes infected with spyware,
        viruses and other malware can be found on document CH001045.


1. Also known as UCE (Unsolicited Commercial Email), spam, not to be confused
with the meat product, is slang commonly used to describe junk e-mail on the
Internet. Spam is e-mail sent to thousands and sometimes millions of people
without prior approval, promoting a particular product, service or a scam to get
other people's money. The first spam e-mail was sent by Gary Thuerk in 1978 an
employee at Digital who was advertising the new DECSYSTEM-2020, 2020T, 2060,
AND 2060T on ARPAnet.

Computer Hope does not participate or endorse spam. We believe the best method
of not receiving spam is simply to delete it and not to participate in the product or
service they are endorsing. In some cases replying to that e-mail indicates that
your e-mail address is valid and your e-mail address may be sent to other spam
lists, although this is prohibited in many countries.

       Additional information about how to help prevent e-mail spam can be found
        on document CH000477.
       See document CH000883 for additional information about nonsense spam

       Below is an monthly poll we conducted August 1 - 31, 2003 to help see how
       much spam messages our visitors receive weekly.

       None (106 votes) 6.26%
       1 to 50 (534 votes)     31.54%
       50 to 100 (385 votes)    22.74%
       Over 100 (635 votes)       37.51%
       Not sure (33 votes) 1.95%
       (Total Votes: 1693 )

   3. When talking in chat or a newsgroup, spam, also known as flooding, is the
      process of posting multiple lines of the same text two or more times. In a
      newsgroup, if a message is posted two or more times, this is also considered
      spam or a flood of messages.

SSL ( secure socket layer) Protocol
The SSL protocol offers security to two application connected through a network.
Specifically, the SSL protocol provides the following:
A mechanism that the applications can use to authenticate each other's identity.
Encryption of the data exchanged by the applications.
When the SSL protocol is used, the target always authenticates itself to the
initiator. Optionally, if the target requests it, the initiator can authenticate itself
to the target. Encryption makes data transmitted over the network intelligible only
to the intended recipient. An SSL connection begins with a handshake during which

the applications exchange digital certificates, agree on the encryption algorithms
to be used, and generate the encryption keys to be used for the remainder of the
The SSL protocol provides the following security features:
Server authentication-WebLogic Server uses its digital certificate, issued by a
trusted certificate authority, to authenticate to clients.
Client authentication-Optionally, clients might be required to authenticate
themselves to WebLogic Server by providing their own digital certificates. This type
of authentication is also referred to as mutual authentication.
Confidentiality-All client requests and server responses are encrypted to maintain
the confidentiality of data exchanged over the network.
Data Integrity-Data that flows between a client and WebLogic Server is protected
from tampering by a third party.
If you are using a Web browser to communicate with WebLogic Server, you can use
the Hypertext Transfer Protocol with SSL (HTTPS) to secure network

SYN attack

Also known as a SYN flood, a SYN attack is a type of Denial of Service (DOS) attack
on a computer or network that floods a network with spoofed SYN packets or
packets that contain an address that never responds to the SYN/ACK requests.

Trojan horse

A program or utility that falsely appears to be a useful program or utility, such as a
screen saver. However, once installed, it performs a function in the background
such as allowing other users to have access to your computer or sending
information from your computer to other computers.


A software program first written Rich Skrenta in 1982 who was a 15-year old high
school student. Known as The Elk Cloner this virus spread to other computers by
monitoring the floppy drive and copying itself to any floppy diskette that was
inserted into the computer. Once a floppy diskette became infected it would infect
all other computers that disk was inserted into, each computer that was infected
would then infect every floppy diskettes inserted into it. A computer that was
infected would also display a short poem on every 50th boot.

Fred Cohen in 1983 later coined the term virus in a 1984 research paper as "a
computer program that can affect other computer programs by modifying them in
such a way as to include a (possibly evolved) copy of itself." Today a computer
virus is a software program, script, or macro that has been designed to infect,
destroy, modify, or cause other problems with a computer or software programs.
Users can protect themselves and remove any viruses on the computer by installing
an antivirus protection program, which is designed to detect, protect, and clean
any computer viruses.

       For more information on computer viruses, see our virus info page.
       Information about creating a virus is found on document CH000653.

        Information about how your computer becomes infected with spyware,
         viruses and other malware can be found on document CH001045.


Short for Wireless Equivalent Privacy, WEP is a type of encryption defined in the
802.11 standard that helps protect a wireless network using encryption. WPA is an
improved encryption standard introduced with 802.11i and a likely replacement for


   1. First developed by John Shoch and Jon Hupp at Xerox PARC in 1978, a worm
      is a destructive software program containing code capable of gaining access
      to computers or networks, and once within the computer or network,
      causes that computer or network harm by deleting, modifying, distributing,
      or otherwise manipulating the data.
   2. Short for Write Once Read Many, WORM is a type of CD that can be written
      to and then read from thereafter. See CD-R for additional information.


   1. Term used to describe a process that is doing nothing but utilizing system
   2. A computer that has been maliciously setup to do work of another program
      or users. A zombie computer is often a computer or server that has been
      compromised to help a malicious user perform a Denial Of Service attack
      (DoS) or DDoS attack.
   3. When referring to chat or IRC, a zombie or ghost refers to a user who has
      lost connection but their user is still logged into the chat server.


Also known as a zombie network, a botnet short for bot network is a group of
infected computers that are under the control of one or more individuals. The
infected computers are used to perform complex tasks that would be hard for one
computer and/or a task someone would not want to be caught doing such as
distributing SPAM e-mail and/or a Distributed Denial of Service (DDoS) attack on
other computers or networks.


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