The Sendmail "decode" alias can be used by remote attackers to overwrite sensitive files.
Older versions of sendmail (generally released before 1992) were configured with a "decode" mail
alias. All mail sent to this alias is piped through the uudecode program.
Since the uudecode format allows the filename to be specified in the encoded data, this
makes it trivially easy for remote users to overwrite any file on the target system. This
vulnerability is compounded by the fact that sendmail is usually configured to run as
root (allowing remote users to overwrite sensitive files like /etc/passwd).