分布式低速率拒绝服务攻击（DLDoS)利用已有网络协议和网络服务中自适应机制的漏洞发起攻击，其攻击效率和隐蔽性比传统洪泛式分布式拒绝服务攻击（DDoS)高得多，更加难于检测和防御。本文对DLDoS攻击进行了建模和形式化，提出了基于拥塞参与度的DLDoS攻击检测过滤方法。实验分析表明，该方法能有效检测DLDoS攻击，并降低误报率。

Distributed Lowrate DenialofService attacks (DLDoS) exploit the vulnerability of the adaptive behaviours exhibited by network protocols and network services. Its attack efficiency and ability of concealment are far higher than the traditional floodingbased DDoS attacks, thus it is harder to detect and defense. In this paper, we first model and formalize the DLDoS attacks, and then propose an approach of detecting DLDoS based on the congestion participation rate (CPR). Experiments and analysis demonstrate that the approach can detect the DLDoS attacks accurately and reduce the false alarm rate drastically.