Historical assessments of combat fratricide reveal principal contributing factors in the effects of stress, degradation of skills due to continuous operations or sleep deprivation, poor situation awareness, and lack of training and discipline in offensive/defense response selection. While these problems are typically addressed in R&D focusing on traditional ground-based combat, there is also an emerging need for improving situation awareness and decision making on defensive/offensive response options in the cyber defense arena, where a mistaken response to an actual or perceived cyber attack could lead to destruction or compromise of friendly cyber assets. The purpose of this report is to examine cognitive factors that may affect cyber situation awareness and describe possible research needs to reduce the likelihood and effects of "friendly cyber fire" on cyber defenses, information infrastructures, and data. The approach is to examine concepts and methods that have been described in research applied to the more traditional problem of mitigating the occurrence of combat identification and fratricide. Application domains of interest include cyber security defense against external or internal (insider) threats.