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2.2.6.2. Anonymous Access

The presence of the /var/ftp/ directory activates the anonymous account.
The easiest way to create this directory is to install the vsftpd package. This package establishes a directory tree for anonymous users and configures the permissions on directories to read-only for anonymous users.
By default the anonymous user cannot write to any directories.

Warning

If enabling anonymous access to an FTP server, be aware of where sensitive data is stored.

Procedure 2.1. Anonymous Upload

  1. To allow anonymous users to upload files, it is recommended to create a write-only directory within the /var/ftp/pub/ directory. Run the following command as root to create such directory named /upload/: 
    ~]# mkdir /var/ftp/pub/upload
  2. Next, change the permissions so that anonymous users cannot view the contents of the directory: 
    ~]# chmod 730 /var/ftp/pub/upload
    A long format listing of the directory should look like this: 
    ~]# ls -ld /var/ftp/pub/upload
drwx-wx---. 2 root ftp 4096 Nov 14 22:57 /var/ftp/pub/upload

    Note

    Administrators who allow anonymous users to read and write in directories often find that their servers become a repository of stolen software.
  3. Under vsftpd, add the following line to the /etc/vsftpd/vsftpd.conf file: 
    anon_upload_enable=YES
  4. In Red Hat Enterprise Linux, the SELinux is running in Enforcing mode by default. Therefore, the allow_ftpd_anon_write Boolean must be enabled in order to allow vsftpd to upload files: 
    ~]# setsebool -P allow_ftpd_anon_write=1
  5. Label the /upload/ directory and its files with the public_content_rw_t SELinux context: 
    ~]# semanage fcontext -a -t public_content_rw_t '/var/ftp/pub/upload(/.*)'

    Note

    The semanage utility is provided by the policycoreutils-python package, which is not installed by default. To install it, use the following command as root: 
    ~]# yum install policycoreutils-python
  6. Use the restorecon utility to change the type of /upload/ and its files: 
    ~]# restorecon -R -v /var/ftp/pub/upload
    The directory is now properly labeled with public_content_rw_t so that SELinux in Enforcing mode allows anonymous users to upload files to it: 
    ~]$ ls -dZ /var/ftp/pub/upload
drwx-wx---. root root unconfined_u:object_r:public_content_t:s0 /var/ftp/pub/upload/
    For further information about using SELinux, see the Security-Enhanced Linux User Guide and Managing Confined Services guides.