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Fix some glaring insecurities in the prototype firewall configurations.

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pass udp from any 53 to ${oip}

allows an attacker to access ANY local port by simply binding his local
side to 53. The state keeping mechanism is the correct way to allow DNS
replies to go back to their source.
This commit is contained in:
Nick Sayer 2001-02-20 19:54:31 +00:00
parent 25801a0e8b
commit 5b9c7d3e5b
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=72772
1 changed files with 4 additions and 8 deletions
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12
etc/rc.firewall
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@ -168,12 +168,10 @@ case ${firewall_type} in
${fwcmd} add deny tcp from any to any setup
# Allow DNS queries out in the world
${fwcmd} add pass udp from any 53 to ${ip}
${fwcmd} add pass udp from ${ip} to any 53
${fwcmd} add pass udp from ${ip} to any 53 keep-state
# Allow NTP queries out in the world
${fwcmd} add pass udp from any 123 to ${ip}
${fwcmd} add pass udp from ${ip} to any 123
${fwcmd} add pass udp from ${ip} to any 123 keep-state
# Everything else is denied by default, unless the
# IPFIREWALL_DEFAULT_TO_ACCEPT option is set in your kernel
@ -270,12 +268,10 @@ case ${firewall_type} in
${fwcmd} add pass tcp from any to any setup
# Allow DNS queries out in the world
${fwcmd} add pass udp from any 53 to ${oip}
${fwcmd} add pass udp from ${oip} to any 53
${fwcmd} add pass udp from ${oip} to any 53 keep-state
# Allow NTP queries out in the world
${fwcmd} add pass udp from any 123 to ${oip}
${fwcmd} add pass udp from ${oip} to any 123
${fwcmd} add pass udp from ${oip} to any 123 keep-state
# Everything else is denied by default, unless the
# IPFIREWALL_DEFAULT_TO_ACCEPT option is set in your kernel