Detections
Analytics
SLEM-05-253025 - SLEM 5 must not allow interfaces to accept Internet Protocol version 4 (IPv4) Internet Control Message Protocol (ICMP) redirect messages by default.
Information
ICMP redirect messages are used by routers to inform hosts that a more direct route exists for a particular destination. These messages modify the host's route table and are unauthenticated. An illicit ICMP redirect message could result in a man-in-the-middle attack.Solution
Configure SLEM 5 to not accept IPv4 ICMP redirect messages by default by running the following command as an administrator:> sudo sysctl -w net.ipv4.conf.default.accept_redirects=0
If "0" is not the system's default value, add or update the following line in "/etc/sysctl.d/99-stig.conf":
> sudo sh -c 'echo "net.ipv4.conf.default.accept_redirects=0" >> /etc/sysctl.d/99-stig.conf'
> sudo sysctl --system
See Also
https://dl.dod.cyber.mil/wp-content/uploads/stigs/zip/U_SLEM_5_V1R4_STIG.zip
Item Details
Category: CONFIGURATION MANAGEMENT
References: 800-53|CM-6b., CAT|II, CCI|CCI-000366, Rule-ID|SV-261316r996418_rule, STIG-ID|SLEM-05-253025, Vuln-ID|V-261316
Plugin: Unix
Control ID: 81dbd5c4960c44e0f6541fb7f2181eefbe818adb4d588a4378ff106c82b1286d