Sendmail Security

A mail administrator should ensure that no one should be able to get special permissions or privileges in the mail system. You should carefully consider the read, write, and execute permissions that are assigned. An unauthorized user with write access can cause considerable damage. You should provide the minimum permissions required. There are many more security measures that can strengthen sendmail security. Some of these measures are listed here:

• Check the file and directory permissions. You should ensure that users have only the minimal permissions required.
• Use the sendmail restricted shell (smrsh) program to limit the programs that can be executed in .forward, aliases, and include files.
• Use the SafeFileEnvironment option to limit where the file system mailbox files can be written.