IT Baseline Protection Manual - The Information Warfare Site

Safeguard Catalogue - Communications Remarks
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partners. Communication on the link as far as the first encrypting network
switching element, however, takes place without encryption, and therefore
holds a residual risk. Authentication is only possible between the switching
elements. The communication partners themselves are not authenticated with
this method.
If sensitive data is transmitted via a network (even within an intranet), it is
advisable to use encryption mechanisms. If the chosen applications do not
have their own encryption mechanisms or if the available procedure is
considered to be too weak, use should be made of the possibility of encryption
on the operating system side. Procedures such as SSL suggest themselves
here, which were designed for transparent encryption at the operating system
level. Depending on the security policy it is also possible to use encrypting
network switching elements, for example in order to implement a virtual
private network (VPN) with a communication partner via the Internet
(appropriate software mechanisms are generally also available in firewall
systems (see Section 7.3 Firewall)).
Considerable planning within the framework of the security policy of a
company or agency is necessary when using encrypted communication and
mutual authentication. In the context of the communication encryption
methods discussed here, particular attention should be paid to the following
points:
- Which procedures are to be used or are offered for encryption (in routers,
for example)?
- Do the encryption mechanisms that are employed support or use existing or
planned standards (IPSec, IPv4, IPv6, IKE)?
- Have sufficiently strong procedures and correspondingly long keys been
chosen, in accordance with the security policy?
- Are the keys held in secure storage?
- Are the keys generated in a secure environment, and do they have a secure
route to the place where they are needed (computer, software component)?
- Are key recovery mechanisms required?
If certificates are used for the authentication of communication partners,
similar questions have to be considered.
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IT-Baseline Protection Manual: Oktober 2000