This threat category covers all threats which involve the deliberate or accidental modification of network databases and services. Threats in this category affect the integrity of data because data may have been corrupted. The integrity of network services is affected because the service may not function in accordance with its intended purpose.
The ``Electronic Intrusion Threat to NS/EP Telecommunications'' report notes the following about unauthorized modification of network databases/services [19]:
Computer intruders have demonstrated a high level of technical skill in modifying PSN databases and subscriber services. They have added unauthorized accounts to service control points, service provisioning systems, digital cross-connect systems, and other network elements. They have added and modified user services, forwarded calls, modified service classes on circuits, and turned off billing on specific circuits. On data networks, computer intruders have changed the routing tables and service descriptions for specific users. This level of penetration and skill demonstrates that computer intruders could seriously compromise NS/EP telecommunications.