They agreed that Graham should set the test for Charles Mabledene. It was
more nor less than that Dragon should get Stern's code. If he had the 'in' at Utting which he claimed to have this should be possible, only loyalty to Moscow Centre would prevent it. If he got the key to the code he would
his loyalty to London Central beyond a
Talking to Strange Men
, Ruth Rendell
A significant security problem for networked systems is
, or at least unwanted, trespass by users or software. User trespass can take the form of unauthorized logon to a machine or, in the case of an authorized
, acquisition of privileges or performance of actions beyond those that have been authorized. Software trespass can take the form of a virus, worm, or Trojan horse.
All these attacks relate to network security because system entry can be achieved by means of a network. However, these attacks are not confined to network-based attacks. A user with access to a local terminal may attempt trespass without using an intermediate network. A virus or Trojan horse may be introduced into a system by means of a diskette. Only the worm is a uniquely network
. Thus, system trespass is an area in which the concerns of network security and computer security overlap.
Because the focus of this book is network security, we do not attempt a comprehensive analysis of either the attacks or the security countermeasures
to system trespass. Instead, in this Part we present a broad overview of these concerns.
This chapter covers with the subject of intruders. First, we examine the nature of the attack and then look at strategies intended for prevention and, failing that, detection. Next we examine the related topic of password management.