“X.800 & RFC 2828”, Who know??

ITU-T Recommendation X.800 (Security Architecture for OSI) and IETF RFC 2828 (Internet Security Glossary) are used as references to systematically evaluate and define security requirements. Though coming from different standardization bodies, the two standards have many points in common. X.800 is used to define general security-related architectural elements needed when protection of communication between open systems is required. X.800 establishes guidelines and constraints to improve existing recommendations and/or to develop new recommendations in the context of OSI. Similarly, RFC 2828 provides abbreviations, explanations and recommendations for information system security terminology.

Both X.800 and RFC 2828 are designed to assist security managers in defining security requirements and possible approaches to meeting those requirements. They also help hardware and software manufacturers to develop security features for their products and services that follow certain standards. X.800 and RFC 2828 both mention several aspects of security systems, namely security threat and attack, security services and mechanisms and security management. This section gives a brief introduction to these standards. We urge readers to read the original standard documents for more information.

Security Threats & Attacks

X.800

According to X.800, ‘A threat to a system security includes any of the following: destruction of information and/or other resources; corruption or modification of information; theft, removal or loss of information and/or other resources; disclosure of information and interruption of services’. Another, clearer definition comes from RFC 2828, which defines a threat as ‘A potential violation of security exists when there is a circumstance, capability, action, or event that could breach security and cause harm’. In other words, a threat is a possible danger that might exploit vulnerability.

RFC 2828

Security attacks (Request for Comments RFC 2828, Internet Security Glossary)

Threat – a potential for violation of security which exists when there is a circumstance, capability, action, or event that could breach security and cause harm. That is, threat is a possible danger that might exploit vulnerabilityAttack – an assault on system security that derives from an intelligent threat; that is, an intelligent act that is a deliberate attempt (especially in the sense of a method or technique) to evade security services and violate the security policy of a system.

Security Attacks

X.800 and RFC 2828 distinguish passive and active attacks :
Passive attacks
Passive attacks are in the nature of eavesdropping on, or monitoring of, transmissions :
a) Release of message contents – encryption is usually used to counter attack

b) Traffic analysis – if contents is closed but the opponent could determine the location and identity of communicating hosts and could observe the frequency and length of messages being exchanged, he may guess the nature of the communication that was taking place.

Passive attacks are very difficult to detect because they do not involve any alteration of data. However, it is feasible to prevent the success of these attacks, usually by means of encryption.

Active attacks

They involve some modification of the data stream or the creation of a false data stream and can be subdivided into 4 categories :

a) A Masquerade takes place when one entity pretends to be a different entity

b) Replay involves the passive capture of a data unit and its subsequent retransmission to produce an unauthorized effect

c) Modification of messages simply means that some portion of a legitimate message is altered

d) The Denial of service prevents or inhibits the normal use or management of communication facilities

What is the OSI ??

OSI [Security Services General Description]
The following are considered to be the security services which can be provided optionally within the framework of the OSI Reference Model. The authentication services require authentication information comprising locally stored information and data that is transferred (credentials) to facilitate the authentication:

Authentication

These services provide for the authentication of a communicating peer entity and the source of data as described below.

Peer entity authentication

This service, when provided by the (N)-layer, provides corroboration to the (N + 1)-entity that the peer entity is the claimed (N + 1)-entity.

Data origin authentication

This service, when provided by the (N)-layer, provides corroboration to an (N + 1)-entity that the source of the data is the claimed peer (N + 1)-entity.

Access control

This service provides protection against unauthorized use of resources accessible via OSI. These may be OSI or non-OSI resources accessed via OSI protocols. This protection service may be applied to various types of access to a resource (e.g., the use of a communications resource; the reading, the writing, or the deletion of an information resource; the execution of a processing resource) or to all accesses to a resource.

Data confidentiality

These services provide for the protection of data from unauthorized disclosure as described below

Connection confidentiality

This service provides for the confidentiality of all (N)-user-data on an (N)-connection

Connectionless confidentiality

This service provides for the confidentiality of all (N)-user-data in a single connectionless (N)-SDU

Selective field confidentiality

This service provides for the confidentiality of selected fields within the (N)-user-data on an (N)-connection or in a single connectionless (N)-SDU.

Traffic flow confidentiality

This service provides for the protection of the information which might be derived from observation of traffic flows.

Data integrity

These services counter active threats and may take one of the forms described below.

Connection integrity with recovery

This service provides for the integrity of all (N)-user-data on an (N)-connection and detects any modification, insertion, deletion or replay of any data within an entire SDU sequence (with recovery attempted).

Connection integrity without recovery

As for the previous one but with no recovery attempted.

Selective field connection integrity

This service provides for the integrity of selected fields within the (N)-user data of an (N)-SDU transferred over a connection and takes the form of determination of whether the selected fields have been modified, inserted, deleted or replayed.

Connectionless integrity

This service, when provided by the (N)-layer, provides integrity assurance to the requesting (N + 1)-entity. This service provides for the integrity of a single connectionless SDU and may take the form of determination of whether a received SDU has been modified. Additionally, a limited form of detection of replay may be provided.

Selective field connectionless integrity

This service provides for the integrity of selected fields within a single connectionless SDU and takes the form of determination of whether the selected fields have been modified.

Non-repudiation

This service may take one or both of two forms.

Non-repudiation with proof of origin

The recipient of data is provided with proof of the origin of data. This will protect against any attempt by the sender to falsely deny sending the data or its contents.

Non-repudiation with proof of delivery

The sender of data is provided with proof of delivery of data. This will protect against any subsequent attempt by the recipient to falsely deny receiving the data or its contents.

Introduce with "ITU-T"

The ITU Telecommunication Standardization Sector (ITU-T) is one of the three sectors (divisions or units) of the International Telecommunication Union (ITU); it coordinates standards for telecommunications.

The standardization work of ITU dates back to 1865, with the birth of the International Telegraph Union. It became a United Nationsspecialized agency in 1947, and the International Telegraph and Telephone Consultative Committee (CCITT, from French: Comite Consultatif International Telephonique et Telegraphique) was created in 1956. It was renamed ITU-T in 1993.

ITU has been an intergovernmental public-private partnership organization since its inception and now has a membership of 191 countries (Member States) and over 700 public and private sector companies as well as international and regional telecommunication entities, known as Sector Members and Associates, which undertake most of the work of the Sector.

ITU-T has a permanent secretariat, the Telecommunication Standardization Bureau (TSB), based at the ITU HQ in Geneva, Switzerland. The elected Director of the Bureau is Malcolm Johnson of the UK. Johnson was elected by the ITU Membership to the directorship for a 4-year term in November 2006 and was reelected for a second term starting January 2011.