Cyber-operation is one of the major implications of rapid development of warfare tools and Methods. Such a big change in warfare is the result of stunning technological breakthroughs in Information and Technology (IT) industry.  IT evolution has increased the level of reliance of the economic and social infrastructures on IT devices, tools and networks. Consequently, it has increased their vulnerability and the possibility of such infrastructures to be targeted by terrorism and cyber-attacks, as major methods of asymmetrical war. Throughout recent decade, the issue of countering "cyber warfare" has always been on top of international security agendas. Certain governments have established new units within their own administrations or militaries in order to monitor legal, political and military aspects of cyber warfare and develop their own Cyber Armies.Regarding International law and particularly International Humanitarian Law (IHL), Since its Prime objective is to protect the lives of civilians and civilian objects in times of International Armed Conflicts (IACs), Any discussion of applicability of IHL rules and regulations, especially  the rules of Conduct of hostilities (i.e., Distinction, proportionality and adoption of precautionary measures) as well as the existing interpretations of such rules to cyber warfare, are of utmost importance given the specific characteristics of cyberspace. IHL is based on objective situations of traditional and classical wars, but cyber-operations happen in a virtual environment. Therefore, there is an essential challenge to apply IHL rules of conflict management to cyber-operations. However, lack of applicable rules of IHL in case of cyber-operations may lead states to codify a new body of IHL applicable to cyber-space. Due to lack of any international legal arrangements designed for conduct of cyber-operations, the article strives to take into account the unique features of cyberspace, the way to interpret and apply the main rules of conduct of hostilities in IHL in the context of cyber-warfare and suggest certain solutions.