Which of the following control is intended to discourage a potential attacker?
A.
Deterrent
B.
Preventive
C.
Corrective
D.
Recovery
Explanation:
Deterrent Control are intended to discourage a potential attacker For your exam you should know below
information about different security controls
Deterrent Controls
Deterrent Controls are intended to discourage a potential attacker. Access controls act as a deterrent to threats
and attacks by the simple fact that the existence of the control is enough to keep some potential attackers from
attempting to circumvent the control. This is often because the effort required to circumvent the control is far
greater than the potential reward if the attacker is successful, or, conversely, the negative implications of a
failed attack (or getting caught) outweigh the benefits of success. For example, by forcing the identification and
authentication of a user, service, or application, and all that it implies, the potential for incidents associated with
the system is significantly reduced because an attacker will fear association with the incident. If there are no
controls for a given access path, the number of incidents and the potential impact become infinite. Controls
inherently reduce exposure to risk by applying oversight for a process. This oversight acts as a deterrent,
curbing an attacker’s appetite in the face of probable repercussions.
The best example of a deterrent control is demonstrated by employees and their propensity to intentionally
perform unauthorized functions, leading to unwanted events.
When users begin to understand that by authenticating into a system to perform a function, their activities are
logged and monitored, and it reduces the likelihood they will attempt such an action. Many threats are based on
the anonymity of the threat agent, and any potential for identification and association with their actions is
avoided at all costs.
It is this fundamental reason why access controls are the key target of circumvention by attackers. Deterrents
also take the form of potential punishment if users do something unauthorized. For example, if the organization
policy specifies that an employee installing an unauthorized wireless access point will be fired, that will
determine most employees from installing wireless access points.
Preventative Controls
Preventive controls are intended to avoid an incident from occurring. Preventative access controls keep a user
from performing some activity or function. Preventative controls differ from deterrent controls in that the control
is not optional and cannot (easily) be bypassed. Deterrent controls work on the theory that it is easier to obey
the control rather than to risk the consequences of bypassing the control. In other words, the power for action
resides with the user (or the attacker). Preventative controls place the power of action with the system, obeying
the control is not optional. The only way to bypass the control is to find a flaw in the control’s implementation.Compensating Controls
Compensating controls are introduced when the existing capabilities of a system do not support the
requirement of a policy. Compensating controls can be technical, procedural, or managerial. Although an
existing system may not support the required controls, there may exist other technology or processes that can
supplement the existing environment, closing the gap in controls, meeting policy requirements, and reducing
overall risk.
For example, the access control policy may state that the authentication process must be encrypted when
performed over the Internet. Adjusting an application to natively support encryption for authentication purposes
may be too costly. Secure Socket Layer (SSL), an encryption protocol, can be employed and layered on top of
the authentication process to support the policy statement.
Other examples include a separation of duties environment, which offers the capability to isolate certain tasks
to compensate for technical limitations in the system and ensure the security of transactions. In addition,
management processes, such as authorization, supervision, and administration, can be used to compensate
for gaps in the access control environment.
Detective Controls
Detective controls warn when something has happened, and are the earliest point in the post-incident timeline.
Access controls are a deterrent to threats and can be aggressively utilized to prevent harmful incidents through
the application of least privilege. However, the detective nature of access controls can provide significant
visibility into the access environment and help organizations manage their access strategy and related security
risk. As mentioned previously, strongly managed access privileges provided to an authenticated user offer the
ability to reduce the risk exposure of the enterprise’s assets by limiting the capabilities that authenticated user
has. However, there are few options to control what a user can perform once privileges are provided. For
example, if a user is provided write access to a file and that file is damaged, altered, or otherwise negatively
impacted (either deliberately or unintentionally), the use of applied access controls will offer visibility into the
transaction. The control environment can be established to log activity regarding the identification,
authentication, authorization, and use of privileges on a system.
This can be used to detect the occurrence of errors, the attempts to perform an unauthorized action, or to
validate when provided credentials were exercised. The logging system as a detective device provides
evidence of actions (both successful and unsuccessful) and tasks that were executed by authorized users.
Corrective Controls
When a security incident occurs, elements within the security infrastructure may require corrective actions.
Corrective controls are actions that seek to alter the security posture of an environment to correct any
deficiencies and return the environment to a secure state. A security incident signals the failure of one or more
directive, deterrent, preventative, or compensating controls. The detective controls may have triggered an alarm
or notification, but now the corrective controls must work to stop the incident in its tracks.
Corrective controls can take many forms, all depending on the particular situation at hand or the particular
security failure that needs to be dealt with.
Recovery Controls
Any changes to the access control environment, whether in the face of a security incident or to offer temporary
compensating controls, need to be accurately reinstated and returned to normal operations. There are several
situations that may affect access controls, their applicability, status, or management.
Events can include system outages, attacks, project changes, technical demands, administrative gaps, and fullblown disaster situations. For example, if an application is not correctly installed or deployed, it may adversely
affect controls placed on system files or even have default administrative accounts unknowingly implemented
upon install. Additionally, an employee may be transferred, quit, or be on temporary leave that may affect policy
requirements regarding separation of duties. An attack on systems may have resulted in the implantation of a
Trojan horse program, potentially exposing private user information, such as credit card information and
financial data. In all of these cases, an undesirable situation must be rectified as quickly as possible and
controls returned to normal operations.
Incorrect Answers:
B: Preventive controls are intended to avoid an incident from occurring
C: Corrective control fixes components or systems after an incident has occurred
D: Recovery controls are intended to bring the environment back
to regular operationsReferences:
CISA Review Manual 2014 Page number 44
Official ISC2 CISSP guide 3rd edition Page number 50 and 51