## R-Commands Vulnerability

### Risk Factor: 9

### Machines Affected:

Packet filtering firewalls and routers that are vulnerable to IP Spoofing, and machines on the local, inside network that have r-commands enabled.

### Description:

The "Berkley R-commands" allow one to gain access to another machine without using a password. This was implemented so that passwords were not transmitted in the clear. The commands are based on a system of "trusted machines." A system of trust that should NOT be trusted, as it is easy to fool (see IP Spoofing vulnerability).

### Consequences:

An intruder can possibly gain root access to an machine through the use of these commands in conjunction with IP Spoofing.

### Fix:

Disable ALL r-commands. To protect against password sniffing on the network, use SSH, or use a One Time Password scheme (such as BellCore's S-Key)