## Documents for rhosts

Code [rcmd001f]

An entry of the form '+ +' in a .rhosts file means that any one on the the Internet can login as the indicated user without a password. This should be removed *immediately* and the system checked for signs of an intrusion.

Code [rcmd002f]

A plus sign (+) in the host field of a .rhosts file means that anyone with the same login ID as the indicated login ID, anywhere on the Internet, can login as that user, without a password. Note that all an intruder has to do is create that login ID on a remote machine that they have privileged access to. This should be removed *immediately* and the system checked for signs of an intrusion.

Code [rcmd003w]

The .rhosts file for the indicated user contains an entry for a host which does not match any of the hosts listed in the RHOST_SITES variable, defined in the 'tigerrc' file.

Code [rcmd004w]

The .rhosts file for the indicated user contains a '+' in the user field. This allows any user on the indicated machine to access the indicated login ID without providing a password. If this is not a captured account, this should be removed immediately and the system checked for signs of an intrusion.

Code [rcmd005i]

The .rhosts file for the indicated user contains an entry which contains a host name, but no username. The user name will default to the login ID of the owner of the .rhosts file. The problem with this is that people often carry around a .rhosts file from host to host, and entries in it become out dated. By allowing the username to default, access to the account can be granted which is not obvious. Entries should be complete with host name and username. They should also be checked and cleaned out regularly.

Code [rcmd006w]

The indicated .rhosts file has permissions other than read and write for the owner of the file. Allowing others to read the .rhosts file provides information about other "trusted" hosts which may allow them to compromise this host, the trusted hosts, or both. The permissions should be at most read and write for the owner of the file. Note that on some systems, because of network file systems, it is necessary to have world read access to the .rhosts file so that client machines can access the .rhosts file. Most systems correctly handle this situation without the need for the world read access. If yours does not, you should bring it to the attention of your vendor.

Code [rcmd007w]

The indicated .rhosts file is a symbolic link. This is not normal and should be looked at to see why it is like this.

Code [rcmd008a]

The indicated .rhosts file is a directory. This may indicate that an intrusion has occurred and the .rhosts directory is being used as a place to store files. This should be examined. The system should also be checked for signs of intrusion if the contents of the directory are unusual. The directory should be removed.

Code [rcmd009f]

The /etc/hosts.equiv file contains a '+' entry. This is a major security hole. It allows anyone to login to the machine as any user except `root'. This needs to be removed immediately. Note that SunOS 4.x systems ship with the '+' entry.

Code [rcmd010i]

The contents of the /etc/hosts.equiv file is listed. The hosts listed here should be examined for correctness.

Code [rcmd011f]

CERT Advisory CA-91:12

A vulnerability exists in the trusted host facility such that the presence of a '-' as the first character of the /etc/hosts.equiv, /etc/hosts.lpd or .rhosts file may allow unauthorized access to the system.

Rearranging the entries such that the entry with the leading '-' is not the first line, or deleting it if it is the only line will solve this problem.

Code [rcmd012f]

The /etc/hosts.equiv file provides access using a netgroup which includes a member of the form (,,). This is a wild card entry which matches any host. This should be corrected immediately.

Code [rcmd013w]

The /etc/hosts.equiv file and $HOME/.rhosts files do not support comments. A commented entry is still valid. It simply indicates a host with the character '#' as the first letter. Since an attempt to comment out an entry indicates that it is no longer needed, it could simply be deleted. Note that comments might (potentially) permit unauthorised access.

Code [rcmd015w]

The indicated .rhosts file contains invalid characters, not expected to be found in a .rhosts file. This file should be examined and the invalid characters removed, as it may contain a typo or possibly a command.