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S-368: RealNetworks Vulnerabilities
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nfssec(5) File Formats Manual nfssec(5) NAME
nfssec - overview of NFS security modes DESCRIPTION
The mount_nfs(1M) and share_nfs(1M) commands each provide a way to specify the security mode to be used on an NFS filesystem through the option. mode can be either or These security modes may also be added to the automount maps. Note that mount_nfs(1M) and automount(1M) do not support at this time. The option on the share_nfs(1M) command line establishes the security mode of NFS servers. If the NFS connection uses the NFS Version 3 protocol, the NFS clients must query the server for the appropriate mode to use. If the NFS connection uses the NFS Version 2 protocol, then the NFS client uses the default security mode, which is currently NFS clients may force the use of a specific security mode by speci- fying the option on the command line. However, if the filesystem on the server is not shared with that security mode, the client may be denied access. If the NFS client wants to authenticate the NFS server using a particular (stronger) security mode, the client wants to specify the secu- rity mode to be used, even if the connection uses the NFS Version 3 protocol. This guarantees that an attacker masquerading as the server does not compromise the client. The NFS security modes are described below. Of these, the modes use the Kerberos V5 protocol for authenticating and protecting the shared filesystems. Before these can be used, the system must be configured to be part of a Kerberos realm. Use authentication. The user's UNIX user-id and group-ids are passed in the clear on the network, unauthenticated by the NFS server . This is the simplest security method and requires no additional administration. It is the default used by HP-UX NFS Version 2 clients and HP-UX NFS servers. Use a Diffie-Hellman public key system which is referred to as in the forthcoming Internet RFC). Use Kerberos V5 protocol to authenticate users before granting access to the shared filesystem. Use Kerberos V5 authentication with integrity checking (checksums) to verify that the data has not been tampered with. User Kerberos V5 authentication, integrity checksums, and privacy protection (encryption) on the shared filesystem. This provides the most secure filesystem sharing, as all traffic is encrypted. It should be noted that performance might suffer on some systems when using depending on the computational intensity of the encryption algorithm and the amount of data being transferred. Use null authentication NFS clients using have no identity and are mapped to the anonymous user by NFS servers. A client using a security mode other than the one with which an HP-UX NFS server shares the filesystem has its security mode mapped to In this case, if the filesystem is shared with users from the client are mapped to the anonymous user. WARNINGS
lists the NFS security services. Do not edit this file. It is not intended to be user-configurable. FILES
NFS security service configuration file SEE ALSO
automount(1M), mount_nfs(1M), share_nfs(1M), rpc_clnt_auth(3N), secure_rpc(3N), nfssec.conf(4). nfssec(5)
