This is a guest post of Antonios Atlasis.
During our blogpost regarding DHCPv6 Guard evasion, one of the side-effects was that Access Control Lists (ACLs) configured to block access to UDP ports 546 can be evaded by abusing (again) IPv6 Extension headers. Having that in mind, we decided to check the effectiveness of Cisco IPv6 ACLs under various scenarios. Our goal was to examine whether the IPv6 ACLs of Cisco routers can be evaded, as well as under which conditions this can take place. To this end, several representative scenarios from enterprise environments or other potential ones are examined.
Continue reading “Evasion of Cisco ACLs by (Ab)Using IPv6 & Discussion of Mitigation Techniques”
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