Information security is a far reaching and often all encompassing topic, but at it’s core information security and the protection of digital assets can be reduced to three central attributes. These are Confidentiality, Integrity and Availability; often referred to as the CIA triangle (not to be confused with the US’ Central Intelligence Agency).
Each factor provides a different and complementary protection to data and all three must be sufficiently preserved to maintain the useful of the information and information systems that are being protected.
Maintaining data’s confidentiality requires ensuring that only those users and/or systems authorised to access the stored information are able to access the protected data.
As a result this aspect is often what first comes to someone’s mind when thinking about information security, the act of preventing those that shouldn’t be able to access the data from doing so. Some of the most commonly understand security systems and processes fall into this category, for example requiring user authentication in the form of a password, or preventing remote access to a restricted resource with a firewall. Removing technology from the process, this is the equivilent of using a lock on the office filing cabinet.
Maintaining data integrity involves ensuring that the data remains correct, whilst in storage or transit, and that only authorised changes are made to the data.
At a highlevel data integrity can be protected using similar controls to those enforcing data confidentiality discussed above, if the data can only be accessed by those that are authorised to view and modify the data are able to access it in the first place then data integrity must be enforced. Unfortunately this is only part of the story as it only protects against the data’s integrity being compromised by a malicious third part. Data integrity can also be compromised by an authorised user changing the data in error, a program handling the data could contain a programming or logic flaw resulting in it changing the data in a way other than desired, or a hardware error could result in the stored data becoming corrupt.
Hashing algorithms like MD5 or SHA1 can be used to determine if the contents of a file has been changed, but this cannot determine if the file has been changed correctly. This highlights one of the key problems within the realm of information security; while data integrity falls under the remit of security there are many different factors, and in the business world many different individuals and/or departments, that can have a direct impact on data integrity; and the overall protection is only as strong as the weakest link.
Maintaining availability of both systems and information is crucial for most IT professionals to continue in gainful employment. As a result a lot of tasks geared towards ensuring systems availability are already incorporated into most business practices, including frequent backups and maintaining standby systems to replace production units in the event of a failure.
Availability of data can be attacked by a malicious user, application or script deleting the data itself; a newer form of attack, ransomware, follows a general trend of monetizing computer attacks involves preventing the legitimate users of the data by cryptographically protecting the data with a key know only to the malicious parties, who then attempt to extort money from the victim in return for the kep to unlock the data.
Alternatively denial of service (DoS) attacks prevent legitimate use of a service by utilising all resources of the server. Like ransomware DoS attacks can be monetized by a malicious party, either before the incident with the potential victim required to pay-up to prevent the attack from occuring in the first incident or being forced to pay to stop an incident that is already in place. Online betting sites were among the first of those businesses to be threatened in this way. The IACIS has a good paper on the topic of cyberextortion [pdf].
— Andrew Waite