Ubuntu-fr

seba_80

un peu plus de securitee reseau

editer le fichier sysctl.conf

gksudo gedit /etc/sysctl.conf

retirer le "#" aux lignes suivantes

#
# /etc/sysctl.conf - Configuration file for setting system variables
# See /etc/sysctl.d/ for additional system variables.
# See sysctl.conf (5) for information.
#

#kernel.domainname = example.com

# Uncomment the following to stop low-level messages on console
#kernel.printk = 4 4 1 7

##############################################################3
# Functions previously found in netbase
#

# Uncomment the next two lines to enable Spoof protection (reverse-path filter)
# Turn on Source Address Verification in all interfaces to
# prevent some spoofing attacks
#net.ipv4.conf.default.rp_filter=1
#net.ipv4.conf.all.rp_filter=1

# Uncomment the next line to enable TCP/IP SYN cookies
#net.ipv4.tcp_syncookies=1

# Uncomment the next line to enable packet forwarding for IPv4
#net.ipv4.ip_forward=1

# Uncomment the next line to enable packet forwarding for IPv6
#net.ipv6.conf.all.forwarding=1


###################################################################
# Additional settings - these settings can improve the network
# security of the host and prevent against some network attacks
# including spoofing attacks and man in the middle attacks through
# redirection. Some network environments, however, require that these
# settings are disabled so review and enable them as needed.
#
# Ignore ICMP broadcasts
net.ipv4.icmp_echo_ignore_broadcasts = 1
#
# Ignore bogus ICMP errors
net.ipv4.icmp_ignore_bogus_error_responses = 1
# 
# Do not accept ICMP redirects (prevent MITM attacks)
net.ipv4.conf.all.accept_redirects = 0
net.ipv6.conf.all.accept_redirects = 0
# _or_
# Accept ICMP redirects only for gateways listed in our default
# gateway list (enabled by default)
# net.ipv4.conf.all.secure_redirects = 1
#
# Do not send ICMP redirects (we are not a router)
net.ipv4.conf.all.send_redirects = 0
#
# Do not accept IP source route packets (we are not a router)
net.ipv4.conf.all.accept_source_route = 0
net.ipv6.conf.all.accept_source_route = 0
#
# Log Martian Packets
#net.ipv4.conf.all.log_martians = 1

rebootez et voila

corrigé suite à la remarque de Pacifick_FR42

Dernière modification par seba_80 (Le 15/11/2011, à 12:01)

seba_80

Re : un peu plus de securitee reseau

ps: MITM = man in the middle

une technique de hack qui met l attaquant au millieu du reseau, donc tout repasse par lui entre les servers et le client

apres modif vous etes blindé

a deconseiller a ceux qui utilisent ubuntu comme router, utilisez plutot pfsense comme router.

Dernière modification par seba_80 (Le 15/11/2011, à 02:34)

Pacifick_FR42

Re : un peu plus de securitee reseau

Merci pour l'info (petite bémol, utilisez gksudo dans le cas d'un lancement graphique par root)