IT Baseline Protection Manual - The Information Warfare Site

Threats Catalogue Deliberate Acts Remarks
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T 2.64 Lack of or defective rules for the RAS system
If no rules or only inadequate ones have been set for the RAS system, this
constitutes a considerable threat to the system as a whole. As a RAS system is
composed of a number of components, the first set of threats comes from the
"Organisational shortcomings" area of the various individual components, as
set forth in the relevant module descriptions.
In the RAS environment, the threats outlined below deserve special mention.
- A RAS system should not be allowed to "grow organically". Instead, use of
RAS access should be preceded by careful planning, irrespective of how
complex access is designed to be. Experience shows that especially where
RAS access is continually extended, complex hardware and software
scenarios can come about which it is then no longer possible to keep under
control. This can result in security settings that are incorrectly selected,
incompatible with each other or which cancel each other out.
- In the absence of a universal and binding security policy, it is usually left
to individual administrators and RAS users to make the security settings
which seem appropriate to them. This can result in incompatible security
settings which either prevent connections from being established or else
allow insecure connections to be established. But since in many cases IT
systems which are linked up via RAS have the same access possibilities as
IT systems which are actually on the LAN, one result may be that the
security of the LAN is compromised.
- The security of a RAS system is based on the interaction of the physical
components (computers, network switching elements), their connection
structure (distribution over the network, connection topology) and the
configurations of the relevant software components. The rules specified in
the RAS security concept and their implementation through corresponding
configuration settings can, however, only deliver the required security if
the system that is actually installed agrees with the planned system. But in
practice changes are often made to the physical design during the
installation phase, for example, due to a lack of detailed information during
the planning phase. If these changes are not recorded, documented and
analysed for possible effects on IT security, then the security of the LAN
can be endangered through incompatibilities of system structure and
configuration of the RAS system.
- If no rules or only inadequate ones have been set for the use of RAS, this
constitutes a special threat. RAS users generally act on their own initiative
when using RAS. If there are no dedicated rules on the use of RAS or if the
users do not know about them, then security weaknesses can be created
unknowingly by the user. Rules whose adherence is the sole responsibility
of the individual user may not always be adhered to in their entirety, for
example due to a lack of technical understanding.
Examples
- Incompatible security settings. The RAS system administrator only allows
triple-DES encrypted connections, but a user has not configured any
encryption for the RAS client. A connection is therefore not established.
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IT-Baseline Protection Manual: Oktober 2000
Lack of or inadequate
planning of the RAS
system
Lack of a RAS security
concept
Installation which does
not comply with the
rules
Lack of or defective
rules for use of RAS