When implementing new security technologies (e.g., cargo scanners at ports), security and defense agencies face important decisions regarding the disclosure of related information to the public. Public disclosure of these technologies can grant adversarial organizations access to critical security‐related information, enabling them to potentially develop or adjust their attack strategies to circumvent defense systems. Alternatively, withholding information about newly deployed technologies can create uncertainties for adversaries regarding the effectiveness of defense systems. In this work, we study defensive information disclosure related to the deployment of new security technology, focusing on the level of technical information released by the defender and how this affects the adversary's (i) belief about the technology's capability (in detecting or otherwise thwarting an attack) and (ii) attack plan. Specifically, we introduce a novel signaling model in which the defender has private information about the (level of) capability of her technology, and decides on the level of related technical detail to be disclosed. The attacker, upon receiving the defender's signal, updates his belief about the capability of the technology and subsequently decides whether to launch an attack. We obtain and prove closed‐form equilibrium solutions to the model and conduct numerical sensitivity analyses to understand how the equilibrium strategies change as the model's data varies. Based on the equilibrium conditions, we also characterize and analyze four unique scenarios that partition the solution space based on relations between the defender's signaling costs.