Network Security

Network security consists of the provisions made in an underlying computer network infrastructure, policies adopted by the network administrator to protect the network and the network-accessible resources from unauthorized access and the effectiveness (or lack) of these measures combined together.

Network security is different from computer security. Securing network infrastructure is like securing possible entry points of attacks on a country by deploying appropriate defense. Computer security is more like providing means of self-defense to each individual citizen of the country. The former is better and practical to protect the civilians from getting exposed to the attacks. The preventive measures attempt to secure the access to individual computers--the network itself--thereby protecting the computers and other shared resources such as printers, network-attached storage connected by the network.
A computer host whose security is compromised is likely to infect other hosts connected to a potentially unsecured network. A computer host's security is vulnerable to users with higher access privileges to those host

Network security starts from authenticating any user. Once authenticated, firewall enforces access policies such as what services are allowed to be accessed by the network users. Though effective to prevent unauthorized access, this component fails to check potentially harmful contents such as computer worms being transmitted over the network. An intrusion prevention system (IPS) helps detect and prevent such malware. IPS also monitors for suspicious network traffic for contents, volume and anomalies to protect the network from attacks such as denial of service. Communication between two hosts using the network could be encrypted to maintain privacy. Individual events occurring on the network could be tracked for audit purposes and for a later high level analysis.

Honeypots, essentially decoy network-accessible resources, could be deployed in a network as surveillance and early-warning tools. Techniques used by the attackers that attempt to compromise these decoy resources are studied during and after an attack to keep an eye on new exploitation techniques. Such analysis could be used to further tighten security of the actual network being protected by the honeypot.

Data Loss Prevention (DLP) is a computer security term referring to systems designed to detect and prevent the unauthorized transmission of information from the computer systems of an organization to outsiders. Also referred to by various vendors as Information Leak Detection & Prevention (ILDP), Information Leak Prevention (ILP), Content Monitoring and Filtering (CMF) or Extrusion Prevention System by analogy to Intrusion-prevention system.

Data security is the means of ensuring that data is kept safe from corruption and that access to it is suitably controlled. Thus data security helps to ensure privacy. It also helps in protecting personal data.

Data corruption refers to errors in computer data that occur during transmission or retrieval, introducing unintended changes to the original data. Computer storage and transmission systems use a number of measures to provide data integrity, the lack of errors.
Data corruption during transmission has a variety of causes. Interruption of data transmission causes information loss. Environmental conditions can interfere with data transmission, especially when dealing with wireless transmission methods. Heavy clouds can block satellite transmissions. Wireless networks are susceptible to interference from devices such as microwave ovens.
Data loss during storage has two broad causes: hardware and software failure. Head crashes and general wear and tear of media fall into the former category, while software failure typically occurs due to bugs in the code.When data corruption behaves as a Poisson process, where each bit of data has an independently low probability of being changed, data corruption can generally be detected by the use of checksums, and can often be corrected by the use of error correcting codes

Database security is the system, processes, and procedures that protect a database from unintended activity. Unintended activity can be categorized as authenticated misuse, malicious attacks or inadvertent mistakes made by authorized individuals or processes. Database security is also a specialty within the broader discipline of computer security.
Traditionally databases have been protected from external connections by firewalls or routers on the network perimeter with the database environment existing on the internal network opposed to being located within a demilitarized zone. Additional network security devices that detect and alert on malicious database protocol traffic include network intrusion detection systems along with host-based intrusion detection systems.
Database security is more critical as networks have become more open.
Databases provide many layers and types of information security, typically specified in the data dictionary, including:
Access control
Auditing
Authentication
Encryption
Integrity controls
Database security can begin with the process of creation and publishing of appropriate security standards for the database environment. The standards may include specific controls for the various relevant database platforms; a set of best practices that cross over the platforms; and linkages of the standards to higher level polices and governmental regulations.
An important procedure when evaluating database security is performing vulnerability assessments against the database. A vulnerability assessment attempts to find vulnerability holes that could be used to break into the database. Database administrators or information security administrators run vulnerability scans on databases to discover misconfiguration of controls within the layers mentioned above along with known vulnerabilities within the database software. The results of the scans should be used to harden the database in order to mitigate the threat of compromise by intruders.
A program of continual monitoring for compliance with database security standards is another important task for mission critical database environments. Two crucial aspects of database security compliance include patch management and the review and management of permissions (especially public) granted to objects within the database. Database objects may include table or other objects listed in the Table link. The permissions granted for SQL language commands on objects are considered in this process. One should note that compliance monitoring is similar to vulnerability assessment with the key difference that the results of vulnerability assessments generally drive the security standards that lead to the continuous monitoring program. Essentially, vulnerability assessment is a preliminary procedure to determine risk where a compliance program is the process of on-going risk assessment.
Application level authentication and authorization mechanisms should be considered as an effective means of providing abstraction from the database layer. The primary benefit of abstraction is that of a single sign-on capability across multiple databases and database platforms. A Single sign-on system should store the database user's credentials (login id and password), and authenticate to the database on behalf of the user.
Another security layer of a more sophisticated nature includes the real-time monitoring of database protocol traffic (SQL) over the network. Analysis can be performed on the traffic for known exploits or network traffic baselines can be captured overtime to build a normal pattern used for detection of anomalous activity that could be indicative of intrusion. These systems can provide a comprehensive Database audit trail in addition to the intrusion detection (and potentially protection) mechanisms.