admin 2022年5月12日21:33:33制度法规评论3 views3176字阅读10分35秒阅读模式


Availability means authorized subjects are granted timely and uninterrupted access to objects. Often, availability protection controls support sufficient bandwidth and timeliness of processing as deemed necessary by the organization or situation. Availability includes efficient uninterrupted access to objects and prevention of denial-of-service (DoS) attacks. Availability also implies that the supporting infrastructure—including network services, communications, and access control mechanisms—is functional and allows authorized users to gain authorized access. 


For availability to be maintained on a system, controls must be in place to ensure authorized access and an acceptable level of performance, to quickly handle interruptions, provide for redundancy, maintain reliable backups, and prevent data loss or destruction. 

There are numerous threats to availability. These include device failure,software errors, and environmental issues (heat, static electricity, flooding, power loss, and soon). Some forms of attack focus on the violation of availability, including DoS attacks, object destruction, and communication interruptions.

Many availability breaches are caused by human error, oversight, or ineptitude. They can also occur because of an oversight in a security policy or a misconfigured security control. 

Numerous counter measures can ensure availability against possible threats.These include designing intermediary delivery systems properly, using access controls effectively,monitoring performance and network traffic, using firewalls and routers to prevent DoS attacks, implementing redundancy for critical systems, and maintaining and testing backup systems. Most security policies, as well as business continuity planning (BCP), focus on the use of fault to lerance features at the various levels of access/storage/security (that is, disk,server, or site) with the goal of eliminating single points of failure to maintain availability of critical systems. 

Availability depends on both integrity and confidentiality. Without integrity and confidentiality,availability cannot be maintained. Concepts, conditions, and aspects of availability include the following:
  •  Usability: The state of being easy to use or learn or being able to be understood and controlled by a subject

  •  Accessibility: Theassurance that the widest range of subjects can interact with a resource regardless of their capabilities or limitations

  • Timeliness: Being prompt, on time,within a reasonable time frame, or providing lowlatency response

  • 可用性,易于使用或学习的状态,或能够被主体理解和控制的状态。

  • 可访问性,保证最广泛的主体能够与资源进行互动,无论其能力或限制如何。

  • 及时性,迅速、准时、在合理的时间范围内,或提供低延迟的回应.



可用性:经过授权的主体被及时准许和不间断地访问客体。可用性提供了经过授权的主体能够访问数据、客体和资源的高级别保证。可用性包括有效地不间断地访问客体和阻止拒绝服务(Denial Of Services,DoS)攻击。基础结构的正常运作。


  • 独立磁盘冗余阵列(RAID)

  • 群集

  • 负载均衡

  • 冗余数据和但原先

  • 软件和数据备份

  • 磁盘映射

  • Co-location和异地备用设施

  • 回滚功能

  • 故障切换配置

  • 破坏可用性的因素:

    • 设备故障

    • 软件错误

    • 环境问题

    • DoS攻击

    • 客体损坏

    • 通信中断


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  • 本文由 发表于 2022年5月12日21:33:33
  • 转载请保留本文链接(CN-SEC中文网:感谢原作者辛苦付出):
                  理解和应用安全概念-3.完整性 http://cn-sec.com/archives/1002569.html


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