Re-enable (default) secure_redirects for ICMP redirect messages

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Raja Grewal 2024-07-24 17:26:50 +10:00
parent d2563ed923
commit 88c88187f2
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2 changed files with 4 additions and 8 deletions

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@ -72,8 +72,7 @@ Various networking components of the TCP/IP stack are hardened for IPv4/6.
from all interfaces to prevent IP spoofing. from all interfaces to prevent IP spoofing.
- Disable ICMP redirect acceptance and redirect sending messages to - Disable ICMP redirect acceptance and redirect sending messages to
prevent man-in-the-middle attacks and minimize information disclosure. If prevent man-in-the-middle attacks and minimize information disclosure.
ICMP redirect messages are permitted, only do so from approved gateways.
- Ignore ICMP echo requests to prevent clock fingerprinting and Smurf attacks. - Ignore ICMP echo requests to prevent clock fingerprinting and Smurf attacks.

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@ -260,6 +260,9 @@ net.ipv4.conf.default.rp_filter=1
## Disable ICMP redirect acceptance and redirect sending messages. ## Disable ICMP redirect acceptance and redirect sending messages.
## Prevents man-in-the-middle attacks and minimizes information disclosure. ## Prevents man-in-the-middle attacks and minimizes information disclosure.
## ##
## https://docs.redhat.com/en/documentation/red_hat_enterprise_linux/6/html/security_guide/sect-security_guide-server_security-disable-source-routing#sect-Security_Guide-Server_Security-Disable-Source-Routing
## https://www.frozentux.net/ipsysctl-tutorial/chunkyhtml/theconfvariables.html
## https://www.debian.org/doc/manuals/securing-debian-manual/network-secure.en.html
## https://askubuntu.com/questions/118273/what-are-icmp-redirects-and-should-they-be-blocked ## https://askubuntu.com/questions/118273/what-are-icmp-redirects-and-should-they-be-blocked
## ##
net.ipv4.conf.all.accept_redirects=0 net.ipv4.conf.all.accept_redirects=0
@ -269,12 +272,6 @@ net.ipv4.conf.default.send_redirects=0
net.ipv6.conf.all.accept_redirects=0 net.ipv6.conf.all.accept_redirects=0
net.ipv6.conf.default.accept_redirects=0 net.ipv6.conf.default.accept_redirects=0
## Accept ICMP redirect messages only for approved gateways.
## If ICMP redirect messages are permitted, only useful if managing a default gateway list.
##
net.ipv4.conf.all.secure_redirects=0
net.ipv4.conf.default.secure_redirects=0
## Ignore ICMP echo requests. ## Ignore ICMP echo requests.
## Prevents clock fingerprinting through ICMP timestamps and Smurf attacks. ## Prevents clock fingerprinting through ICMP timestamps and Smurf attacks.
## ##