CCE-95075-8Platform: cpe:/o:debian:debian_linux:11.x, cpe:/o:ubuntu:ubuntu_linux:20.04, cpe:/o:ubuntu:ubuntu_linux:22.04, cpe:/o:ubuntu:ubuntu_linux:23.04 | Date: (C)2020-10-15 (M)2023-09-01 |
ICMP Redirects are used to send routing information to other hosts. As a host itself does not act as a router (in a host only configuration), there is no need to send redirects.
Rationale:
An attacker could use a compromised host to send invalid ICMP redirects to other router devices in an attempt to corrupt routing and have users access a system set up by the attacker as opposed to a valid system.
Fix:
Set the net.ipv4.conf.all.send_redirects and net.ipv4.conf.default.send_redirects parameters to 0 in /etc/sysctl.conf and run sysctl -p command:
net.ipv4.conf.all.send_redirects=0net.ipv4.conf.default.send_redirects=0
Modify active kernel parameters to match:
# /sbin/sysctl -w net.ipv4.conf.all.send_redirects=0
# /sbin/sysctl -w net.ipv4.conf.default.send_redirects=0
# /sbin/sysctl -w net.ipv4.route.flush=1
Parameter:
[no/yes, no/yes]
Technical Mechanism:
Set the net.ipv4.conf.all.send_redirects and net.ipv4.conf.default.send_redirects parameters to 0 in /etc/sysctl.conf:
net.ipv4.conf.all.send_redirects=0 net.ipv4.conf.default.send_redirects=0
Modify active kernel parameters to match:
# /sbin/sysctl -w net.ipv4.conf.all.send_redirects=0
# /sbin/sysctl -w net.ipv4.conf.default.send_redirects=0
# /sbin/sysctl -w net.ipv4.route.flush=1
CCSS Severity: | CCSS Metrics: |
CCSS Score : 5.5 | Attack Vector: LOCAL |
Exploit Score: 1.8 | Attack Complexity: LOW |
Impact Score: 3.6 | Privileges Required: NONE |
Severity: MEDIUM | User Interaction: REQUIRED |
Vector: AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N | Scope: UNCHANGED |
| Confidentiality: HIGH |
| Integrity: NONE |
| Availability: NONE |
| |
References: Resource Id | Reference |
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SCAP Repo OVAL Definition | oval:org.secpod.oval:def:65922 |
SCAP Repo OVAL Definition | oval:org.secpod.oval:def:87279 |
SCAP Repo OVAL Definition | oval:org.secpod.oval:def:92257 |
SCAP Repo OVAL Definition | oval:org.secpod.oval:def:85151 |