多级安全数据库系统(MLS/DBMS)中并发控制协议并不能彻底消除所有的隐蔽通道.在隐蔽通道无法避免的情况下,已渗透的恶意事务可以利用隐蔽通道泄漏和篡改机密信息.为提高数据库的可生存性,首先分析了MLS/DBMS系统中的隐蔽通道,通过对真实情况的参数模拟和实验分析,结合恶意事务特征和隐蔽通道带宽的异常改变,给出可生存DBMS中的同谋事务和恶意事务的检测,并提出了同谋用户造成隐蔽通道传递性的机理以及恶意噪声事务对其的影响.
Current concurrency control protocols can not eliminate all covert channels in multi-level secure database managewent systems(MLS/DBMS).Existence of covert channels leads penetrated malicious transactions leak and interpolate confidential information. To improve database survivability, covert channels in MLS/DBMS are firstly analyzed. Then Conspired and malicious noise transactions can be detected based on malicious transaction characteristics and abnormal varieties of covert channel capacities by simulated parameters and experiments according to real systems. Further, transitive property of multi-conspiracies along with the influence of malicious noise transaction is analyzed.