Sun Solaris 7.0_x86
  Sun Solaris 7.0
  Sun Solaris 2.6_x86
  Sun Solaris 2.6


  Solaris is the variant of the UNIX Operating System distributed
  by Sun Microsystems. Solaris is a versatile operating system
  designed for use with machines as small as desktop systems and
  as large as enterprise systems.


  A problem with the ftp daemon included with the Solaris
  Operating Environment could allow remote users to gain
  access to names of valid user accounts. Prior to logging
  in, while in.ftpd is still negotiating the session, it is
  possible to present a request for a change of working 
  directory (CWD) to the ftp daemon. If the account is valid,
  the daemon will issue a request for login and password. If
  not, the daemon returns an error message stating that the
  login name is not valid.

  Therefore, it is possible for a remote user to gather the
  names of local users on a Solaris system with ftp services.
  This may lead to spamming, or further compromise.

  nc 21
  220 gsmms0 FTP server (SunOS 5.6) ready.
  cwd ~netadm
  530 Please login with USER and PASS.
  cwd ~xyz
  530 Please login with USER and PASS.
  550 Unknown user name after ~