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Old 09-01-2006, 09:23 AM   #1
jfabiani
Member
 
Registered: Apr 2003
Location: Woodland, CA
Distribution: RH 8.0
Posts: 33

Rep: Reputation: 15
Unhappy ftp security


security with FTP
From:
johnf <jfabiani@yolo.com>
Reply-To:
jfabiani@yolo.com
Date:
Thursday 31 August 2006 13:50:23
Groups:
alt.os.linux.suse
no references

Hi,
I'm new to the FTP server world. I have opened the port and setup the
VSFTPD as best I can figure. I am able to have other connect using there
passwords and thought I was OK. But today I noticed my internet access
light was blinking and I checked my server for access and found:
netstat -a | grep ESTABLISHED
TCP 0 34 server1.mydomain:ftp excalibur2.anyfas:57353 ESTABLISHED

Does the above mean that someone was able to get into the ftp server? I
think so. Below is my vsftd.conf file. Can someone point out what I'm
doing wrong. Thanks...


# Example config file /etc/vsftpd.conf
#
# The default compiled in settings are fairly paranoid. This sample file
# loosens things up a bit, to make the ftp daemon more usable.
# Please see vsftpd.conf.5 for all compiled in defaults.
#
# If you do not change anything here you will have a minimum setup for an
# anonymus FTP server.
#
# READ THIS: This example file is NOT an exhaustive list of vsftpd options.
# Please read the vsftpd.conf.5 manual page to get a full idea of vsftpd's
# capabilities.

# General Settings
#
# Uncomment this to enable any form of FTP write command.
#
write_enable=YES
#
# Activate directory messages - messages given to remote users when they
# go into a certain directory.
#
dirmessage_enable=YES
#
# It is recommended that you define on your system a unique user which the
# ftp server can use as a totally isolated and unprivileged user.
#
#nopriv_user=ftpsecure
#
# You may fully customise the login banner string:
#
ftpd_banner="Welcome to JF COMPUTER SOLUTIONS FTP service."
#
# You may activate the "-R" option to the builtin ls. This is disabled by
# default to avoid remote users being able to cause excessive I/O on large
# sites. However, some broken FTP clients such as "ncftp" and "mirror"
assume
# the presence of the "-R" option, so there is a strong case for enabling
it.
#
#ls_recurse_enable=YES
#
# You may specify a file of disallowed anonymous e-mail addresses.
Apparently
# useful for combatting certain DoS attacks.
#
#deny_email_enable=YES
#
# (default follows)
#
#banned_email_file=/etc/vsftpd.banned_emails
#
# If enabled, all user and group information in
# directory listings will be displayed as "ftp".
#
#hide_ids=YES

# Local FTP user Settings
#
# Uncomment this to allow local users to log in.
#
local_enable=YES
#
# Default umask for local users is 077. You may wish to change this to 022,
# if your users expect that (022 is used by most other ftpd's)
#
#local_umask=022
#
# Uncomment to put local users in a chroot() jail in their home directory
# after login.
#
chroot_local_user=YES
#
# You may specify an explicit list of local users to chroot() to their home
# directory. If chroot_local_user is YES, then this list becomes a list of
# users to NOT chroot().
#
#chroot_list_enable=YES
#
# (default follows)
#
#chroot_list_file=/etc/vsftpd.chroot_list
#
# The maximum data transfer rate permitted, in bytes per second, for
# local authenticated users. The default is 0 (unlimited).
#
#local_max_rate=7200


# Anonymus FTP user Settings
#
# Allow anonymous FTP?
#
anonymous_enable=NO
#
# Anonymous users will only be allowed to download files which are
# world readable.
#
#anon_world_readable_only=YES
#
# Uncomment this to allow the anonymous FTP user to upload files. This only
# has an effect if the above global write enable is activated. Also, you
will
# obviously need to create a directory writable by the FTP user.
#
#anon_upload_enable=YES
#
# Default umask for anonymus users is 077. You may wish to change this to
022,
# if your users expect that (022 is used by most other ftpd's)
#
#anon_umask=022
#
# Uncomment this if you want the anonymous FTP user to be able to create
# new directories.
#
#anon_mkdir_write_enable=YES
#
# Uncomment this to enable anonymus FTP users to perform other write
operations
# like deletion and renaming.
#
#anon_other_write_enable=YES
#
# If you want, you can arrange for uploaded anonymous files to be owned by
# a different user. Note! Using "root" for uploaded files is not
# recommended!
#
#chown_uploads=YES
#chown_username=whoever
#
# The maximum data transfer rate permitted, in bytes per second, for
anonymous
# authenticated users. The default is 0 (unlimited).
#
#anon_max_rate=7200


# Log Settings
#
# Log to the syslog daemon instead of using an logfile.
#
syslog_enable=YES
#
# Uncomment this to log all FTP requests and responses.
#
#log_ftp_protocol=YES
#
# Activate logging of uploads/downloads.
#
#xferlog_enable=YES
#
# You may override where the log file goes if you like. The default is shown
# below.
#
#vsftpd_log_file=/var/log/vsftpd.log
#
# If you want, you can have your log file in standard ftpd xferlog format.
# Note: This disables the normal logging unless you enable dual_log_enable
below.
#
#xferlog_std_format=YES
#
# You may override where the log file goes if you like. The default is shown
# below.
#
#xferlog_file=/var/log/xferlog
#
# Enable this to have booth logfiles. Standard xferlog and vsftpd's own
style log.
#
#dual_log_enable=YES
#
# Uncomment this to enable session status information in the system process
listing.
#
#setproctitle_enable=YES

# Transfer Settings
#
# Make sure PORT transfer connections originate from port 20 (ftp-data).
#
connect_from_port_20=YES
#
# You may change the default value for timing out an idle session.
#
#idle_session_timeout=600
#
# You may change the default value for timing out a data connection.
#
#data_connection_timeout=120
#
# Enable this and the server will recognise asynchronous ABOR requests. Not
# recommended for security (the code is non-trivial). Not enabling it,
# however, may confuse older FTP clients.
#
#async_abor_enable=YES
#
# By default the server will pretend to allow ASCII mode but in fact ignore
# the request. Turn on the below options to have the server actually do
ASCII
# mangling on files when in ASCII mode.
# Beware that turning on ascii_download_enable enables malicious remote
parties
# to consume your I/O resources, by issuing the command "SIZE /big/file" in
# ASCII mode.
# These ASCII options are split into upload and download because you may
wish
# to enable ASCII uploads (to prevent uploaded scripts etc. from breaking),
# without the DoS risk of SIZE and ASCII downloads. ASCII mangling should be
# on the client anyway..
#
#ascii_upload_enable=YES
#ascii_download_enable=YES
#
# Set to NO if you want to disallow the PASV method of obtaining a data
# connection.
#
#pasv_enable=NO

# PAM setting. Do NOT change this unless you know what you do!
#
pam_service_name=vsftpd

# Set listen=YES if you want vsftpd to run standalone
#
#listen=YES

# Set to ssl_enable=YES if you want to enable SSL
ssl_enable=NO
 
Old 09-01-2006, 09:36 AM   #2
w3bd3vil
Senior Member
 
Registered: Jun 2006
Location: Hyderabad, India
Distribution: Fedora
Posts: 1,191

Rep: Reputation: 49
the vsftpd file seems to be ok, since you dont have anonymous connections allowed. what you should try looking at is the vsftpd.log file, but I dont think you have that enabled. anyhow, enable it and then always keep an eye on it.
someone might have brute forced your ftp to gain access to it, try john the ripper and crack your own shadow file and change the weak passwords.
 
Old 09-01-2006, 10:02 AM   #3
jfabiani
Member
 
Registered: Apr 2003
Location: Woodland, CA
Distribution: RH 8.0
Posts: 33

Original Poster
Rep: Reputation: 15
Thanks - my guess was right someone had cracked the ftp - right. I do have two users with easy passwords. I wonder does the VSFTPD.conf file allow root access?

John
 
Old 09-01-2006, 10:21 AM   #4
w3bd3vil
Senior Member
 
Registered: Jun 2006
Location: Hyderabad, India
Distribution: Fedora
Posts: 1,191

Rep: Reputation: 49
vsftpd doesnt even let a user enter password if he types root as the username.
 
Old 09-08-2006, 06:35 AM   #5
amitsharma_26
Member
 
Registered: Sep 2005
Location: New delhi
Distribution: RHEL 3.0/4.0
Posts: 777

Rep: Reputation: 31
Quote:
Originally Posted by jfabiani
Thanks - my guess was right someone had cracked the ftp - right. I do have two users with easy passwords. I wonder does the VSFTPD.conf file allow root access?

John
By default vsftpd doesnt allow root to log into ftp.
You got to comment 'root' in /etc/vsftpd.ftpusers & /etc/vsftpd.user_list to let root log into ftp & the same works for other users as well. Any user name which has mentioned its user_id in these of the two of above files will be denied to log into ftp.
 
  


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