Executive brief
The remote shell service (in.rshd), used for executing commands on remote computers, contains a flaw that allows unauthorized users to log in without a valid username. An attacker can exploit this to gain access to the system and execute arbitrary commands. This could lead to a total compromise of the affected server, including data theft or service disruption.
Technical details
The in.rshd daemon fails to properly validate or reject NULL usernames during the authentication handshake. By supplying a NULL value for the username, a remote, unauthenticated attacker can bypass standard access controls. Once connected, the attacker can execute arbitrary commands with the privileges of the shell session. This vulnerability is exploitable over the network without user interaction.
Affected products
- unknown in.rshd
Timeline
- 1997-01-01: disclosed