In object oriented paradigm, a concurrent system can be regarded as a collection of autonomous active objects which synchronize and communicate through shared passive objects. In this paper, we propose a UML-based approach to specify secured, fine-grained concurrent access to shared resources ensuring data integrity and security. The goal of the approach is to develop the UML specification with precise executional semantics, yet independent of low-level synchronization primitives and implementation environment. The approach is largely inspired from the language constructs of CDL*. A light-weight extension of UML 2.0 meta-model is proposed for the required constructs and semantics. UML protocol statemachine is used to define the access protocol for shared resources and UML activity is used to specify the behavior of methods implementing plausibly concurrent operations. The UML activity construct is extended to support concurrency features; synchronization regions, mutual exclusion and conditional synchronization not supported in current UML2.0 semantic model. The approach can be easily extended to a programming framework of design and coding.