Services supported by ONA networks require much more software than the traditional Plain Ordinary Telephone Services [10]. As an increasing number of network services are created and deployed, software will be an even more dominant component of telecommunications networks. ONA not only increases the amount of software used, ONA also greatly increases the number of users who have access to network software. By giving more users access to network software, ONA increases the potential for hostile users.
ONA also increases the number of levels of access to software. Software which previously was only accessible by the carrier may be accessible in varying degrees to vendors and customers of enhanced services. For example, ONA will require that access to existing switch call processing software be provided at an elemental service level [10]. If proper security mechanisms are not used, the increasing accessibility of network software will provide hackers and saboteurs with the opportunities to impact the PSN. For example, the accessibility of network software may provide hackers and saboteurs with the opportunity to damage routing databases.
As noted in a study by the National Research Council, as more levels of network software are made visible to users for purposes of affording parity of network access, users will learn more about the inner workings of the network software, and those with hostile intent will learn more about how to abuse the network [4].
Vulnerabilities associated with software have an impact on the integrity and privacy of the software. As computer intruders learn more about how the network software is used, it is possible for computer intruders to have an impact on the availability, integrity, and privacy of network functions. Fraud may also result.