A current trend in the web services community is to define coordination mechanisms to execute collaborative tasks involving multiple organizations. Following this tendency, this work presents a dependable (i.e., intrusion-tolerant) infrastructure for cooperative web services coordination that is based on the tuple space coordination model. This infrastructure provides decoupled communication and implements several security mechanisms that allow reliable coordination even in presence of malicious components. This work also investigates the costs related to the use of this infrastructure and possible web service applications that can benefit from it.