In the offence of traditional criminal damage, criminal behavior is carried out towards movable or immovable objects that are tangible and touchable in the outside world, but human advances in the field of information technology have caused the formation of various information that are stored in spaces such as data carriers. Additionally, there are various types of computer or telecommunication devices, such as laptops, tablets and smartphones, that may contain important data. Sabotage acts that lead to the destruction of computer information or the impairment of computer or telecommunication systems have a different form that is different from its traditional form. So, in Iranian law, computer criminal damage is provided in two forms, which are: destruction of computer data and disruption of computer or telecommunication systems. In contrast, in English and Welsh law, the offense of unauthorised modification of computer material, in order to deal with any unauthorized act that is committed with the intention of impairing the operation of the computer, preventing access to the computer program or data, or impairing the operation of the computer program or reliability of the computer data is criminalized. The comparison of the aforementioned penal systems makes it clear that there are some flaws in the approach of the Iranian legislator, including ignoring some technological advances such as the Internet of Things (IoT) and also the non-recognition of criminal recklessness, which, amending them, will have good effect in dealing more effectively with computer vandals and issuing concrete criminal decisions.