DATA SECURITY

Security considerations apply not only to the data held in the database Breaches of security may affect other parts of the system which may in turn affect the database Consequently database security encompasses; hardware, software, people, and data

Why data security? Increasing amounts of crucial cooperate data is being stored on a computer And acceptance that any loss or unavailability of this data could prove to be disastrous

Database security is considered in relation to the following situation Theft and fraud Loss of confidentiality Loss of privacy Loss of integrity Loss of availability

Such situations as above the organization should seek ways or controls which to reduce the risk i.e. the possibility of incurring loss or damage The situations are closely related in that and action that lead to a loss in one area may lead to a loss in another Events such as fraud or loss of privacy may arise because of either intentional or unintentional act and do not necessarily arise to any detectable changes in the database or the computer system

Theft and Fraud Affect not only the database environment but the entire organization Also theft and fraud do not alter data such as loss of privacy and confidentiality

Confidentiality Refers to the need to maintain secrecy over data usually any that is critical to the organization Breaches of security resulting to loss of confidentiality leads to loss of competitiveness of the organisation

Privacy Refers to the need to protect data about individuals Loss of privacy leads to legal action being taken against organisation

Loss of integrity Leads to corrupted or invalid data which seriously affect the organisation

Loss of availability Means that the data or the system cannot be accessed which may lead to loss of financial performance In some cases events that lead to loss of availability may lead to loss of data or data corruption

Data Security DS aims to minimize losses caused by anticipated events in a cost effective manner without constraining the users

Threats Any situation or event that may adversely affect the system intentionally or accidentally and consequently the organization a threat may be caused by a situation or event involving a person that is likely to bring harm to the organization Harm may be tangible such as loss of hardware, software or data or intangible such as loss of credibility or client confidence As a minimum an organization should identify all the possible threats Threats may be caused by unintentional or intentional actions Intentional actions are caused by people that may be perpetrated by both authorized and unauthorized users, some of whom may be external to the organization Ant threats must be viewed as potential breach of security which if successful have a certain impact A breach of security or one threat may lead to more than one situation or loss. For example disclosure of unauthorized data or viewing may lead to theft and fraud, loss of privacy and confidentiality for the organization

THREATS CONT… The extend to which an organization suffers because of threat succeeding depend on a number of factors such as existence of the counter measures or contingence plans in place If a hardware failure occurs corrupting secondary storage the recovery will depend on a number of factors which include when the last backups where done and the time needed to restore the system And organization needs to identify the type of threat it is subjected to and initiate appropriate plans and counter measures bearing in mind the cost of implementing them The organization should concentrate on potential threats that results in great inconvenience Rare threats should be considered if their impact is significant How to protect a computer system using computer based controls Authorization Defin:The granting of right or privileges tha enables a subject to have the legitimate access to the system or a system’s object. Authorization controls can be built into the software and govern not only what the system or object a specified user may do with it. Authorization controls are sometimes called access controls. The process of authorization involves authentication of subjects requesting access to objects where objects represents a database table,view,triggeror any other object that can be created within the system.

AUTHENTICATION Defn: a mechanism that determines whether the user is he/she claims to be. A system administrator is responsible for allowing users to have access to a computer system by creating individual accounts. Each user is given the unique identifier which is used by the operating system to determine who they are. Associated with each identifier is a password chosen by the user and known to the operating system A separate procedure have to be taken for users to get access to the DBMSs or application program. However other DBMSs maintain a list of those entries valid user identifiers and associated password which can be distinct from o/s is lost. The list are validated against those of o/s on the current user ‘s login identifier. This prevents the user from logging to the database with one name. Privileges Once the user is given the permission to use DBMS, various other privileges may also be automatically associated with it. Example privileges may include the right to access and create certain database objects such as relations, views, indexes or to run various DBMS utilities. They are granted to users to accomplish the tasks required for their particular jobs. Some DBMSs operate as closed systems so that while users may be authorized to access DBMS,they require authorization to access specific fields. An open system allows users to have access to all objects with the database.

VIEWS Defin:It is a virtual relation that does not actually exist in the database, but is produced upon request by a particular user at a time of request. The view mechanism provides a powerful and flexible security mechanism by hiding parts of the database from certain users. The users is not aware of the existence of any attributes or rows missing from the view. A view can be defined over several relations with the user being granted the appropriate privilege to use the base relations. BACK UP AND RECOVERY Defn: back up is the process of periodically taking a copy of the database and log file onto offline storage media. A DBMS should provide back up facilities to assist with the recovery of database following a failure. It is always advisable to make back –up copies of the database and log files at regular intervals and to ensure that copies are in separate locations. JOURNALING Defin:The process of keeping and maintaining a log file{journal}of all changes made in the database to enable recovery to be undertaken in the event of failure.

Journaling conti Advantages In the event of failure of the database can be recovered to the last known consistent state using back up copy of the database and the information contained in the log file. Integrity Integrity constraints also contributes to maintaning a secure database system by preventing data from being invalid and hence giving misleading or incorrect results. Encryption Defn: The encoding of data by a special algorithm that reads the data as unreadable by any program without a decryption key. It protects the data transmitted over communication lines. Number of techniques are used to encode data to conceal information 1.To transmit data securely over insecure networks requires the us of ptosystem which includes: A.an encryption key to encrypt the data into plain text. B. an encryption algorithm that with the encryption key transforms the plain text into cipher text. C.a decryption key to decrypts the cipher text D.a decryption algorithm that transforms cipher back to plain text.

SECURITY IN ORACLE Privileges: Defn: it is the right to execute a particular type of SQLstatement or access to another user ‘s objects. Oracle privileges include A. connect to the database. B. create a table rowsfrom another user /s table. Two types of privileges: System Right to perform a practical action or to perform an action on any schema objects of particular type e.g. privilege to create tables paces and to create users in the database. System privileges are granted to or revoked from users SQL GRANT and REVOKE statement.

Privileges Object privileges It is a privilege or right to perform a particular action on a specific table, view, procedure, function or package. Different object privileges are available to different types of object example. Privilege to delete rows from staff table. SQL statement. SQL>DELETE FROM staff WHERE staff no= ‘5914’; A user automatically has all object privileges for schema objects contained in his /her schema. a user can grant an object privilege on any schema object he/she owns to any user or roles Roles. Privileges can be granted to users explicitly. Example: grant the privilege to insert rows into the property for rent table for the user Beech. GRANT INSERT ON PROPERTYFOR RENT TO Beech;

privileges Users can grant the privilege to select,insert and update rows frompro pertY for rent table to the named Assistant then in turn can be granted to Beech. GRANT INSERT ON ‘MANAGER’ PROPERTFOR RENT TO ‘ASSISTANT GRANT SELECT ON ‘MANAGER’ PROPERTFOR RENT TO ‘ASSISTANT

DBMS AND WEB SECURITY PROXY SERVERS It is a computer thatsitt between the web browser and web server. It intercepts all request to the web server to determine if it can fulfill the requests itself if not forwarded to the web server. they have two main purposes: *improve perfomance Since a proxy server saves the results of all requests for certain amount of time,it can significantly improve the perfomance for group of users. Example: Assume that user A and user B access the web thru a proxy server.First the user A request the web page and slightly user B requests the same page.instead of forwarding the requests to the web server where the page resides,the proxy server simply returns the cache page that had already fetched for user A.

Filter requests P roxy servers can also be used to filter requests. Example. An organization might use the proxy server to prevent its employees from accessing a specific websites Firewalls Defn: it is a system designed to prevent unauthorized access to or from a private network. They are frequently used to prevent unauthorized internet users from accessing private networks connected to the internet especially intranet. Types: 1.packet filter. Looks at each packet entering or leaving the n/w and accepts or rejects it based on user defined rules. It is susceptible to IP spoofing IP spoofing-is a technique used to gain unauthorized access to computers whereby the intruder sends message to the computer with an IP address indicating that the message is coming from a trusted port. Application gateway Which applies to a specific application such as telnet servers and FTP. This is a a very effective mechanism, but degrade performance. Circuit-level gateway Which applies security mechanism to UDP connection is established once the has been made packets can flow between hosts without further checking.

Security mechanism continued proxy server which intercepts all messages entering or leaving the n/w. The proxy server in effect hides the true n/w addresses. Message Digest algorithms and digital signatures A message digest algorithm or one way harsh function takes an arbitrary- sized string. Digital certificates a digital certificates is an attachment to an electronic message used for security purposes. And most commonly used to verify that user sending a message is he/she claims to be,and to provide the receiver with the means to the encode a reply. An individual wishing to send an encrypted message applies for a digital certificate from Certificate Authority. The CA issues on encrypted digital certificate containing the applicant’s public key and a variety of identification information. the recipient of an encrypted message uses the CA’s public key to decode the digital certificate attached to the message., verifies it as issued by CA. and then obtains the sender’s public key and identification information held within the certificate. The most common used standard for digital cetificates is X.509.

kerberos It is a server of of secured usernames and passwords named after three- headed monster in Greek mythology that guarded the gate of hell. Importance. It provides one centralized security server for data and resources on the n/w.database access,login,authorization control and security features are centralised finished Kerberos servers. Secure sockets,layer and secure HTTP Many large internet product developers agreed to use an encryption protocol known as secure socket layer (SSL) developed by Netscape for transmitting private document over internet. It works by using a private key to encrypt data that is transferred over SSL connection and use this protocol to obtain confidential use of information such as credit card. Another protocol for transmitting data is over the web is secure HTTP(SHTTP). It is the modified version of the standard HTTP protocol was developed by Enterprise integrated technologies. Wheres the SSL creates a secure connection between a client and server over which any amount of data securely S Http is designed to transmit individual message securely.

Ssl continued Through the use of cryptographic techniques such as encryption and digital signatures these protocols: 1. allow web browser and servers to authenticate each other. 2. permit web-site owners to control access to particular servers, directory or servers. 3. allow sensitive information for example credit cards numbers to be shared between browsers and server get remain inaccessible to third parties. 4.ensure that data exchanged betwn browser and server is reliable that is can not be corrupted either accidentally or deliberately without detection. Secure electronic transactions and secure transaction technology SET protocol is an open interoperable standard for processing credit cards Over the internet created jointly by Netscape,Microsoft Visa, Master card. SET ‘s goal is to allow credit card transactions to be as simple and secure over the internet as they are in retail shops.

Java security Safety and security are integral parts of Java with the sandbox ensuring that an untrusted,possibly malicious application can not gain access to the system’s resources. To implement three components are used. (a) class loader Class loader as well as loading each required class and checking if it is in the correct format, additionally checks that the application /applet does not violate system security by allocating a namespace. A class loader never allows a class fro a less protected namespace to replace that of name space. (b) the bytecode verifier JVM (java virtual machine) will, allow an applet to run its code must be verified. The verifier assumes that all code is meant to crash or violate system security and perform a series of checks. Typical checks include 1.Compiled code is correctly formatted 2.internal stacks will over through /under throw 3. no illegal data conversions will occur. E.g.

continued The security Manager Performs runtime verification of potentially dangerous that is methods that I/o n/w access or wish to give a class loader. Active X Security it is different from Java Applets Each Active X can be digitally signed by its author using a system called Authenticode trade mark. The digital signatures are certified by CA. Before the browser downloads an Active X control has not been certified by unknown CA. It represents a dialogue box warning the user that this action may not be safe. The user can then about the transfer or continue and accept the consequences.