Hi @cooperrocks78
It seems like you have implemented IPv6 RA Guard and DHCP Guard policies on your access switches, but the pentesters were still able to spoof an IPv6 DHCP attack. This suggests that the configuration may not be fully effective or properly applied. Let's analyze the situation and identify potential issues:
1. RA Guard and DHCP Guard Limitations
- RA Guard: RA Guard is designed to block rogue Router Advertisement (RA) messages. However, it has limitations, especially if the attacker uses advanced techniques like fragmentation or tunneling to bypass the guard.
- DHCP Guard: DHCP Guard is designed to block unauthorized DHCP servers. However, it must be configured correctly and applied to the correct interfaces or VLANs.
2. Configuration Review
Based on the output you provided, the policies are applied at the VLAN level. However, there are a few potential issues to consider:
- Device Role: The
device-role in your RA Guard and DHCP Guard policies is set to host and dhcp client, respectively. This is correct for end-user devices, but you need to ensure that the policies are applied to the correct interfaces (e.g., access ports where workstations are connected).
- Policy Application: The policies are applied to VLANs, but VLAN-level application may not be sufficient. RA Guard and DHCP Guard are most effective when applied at the interface level (e.g., on access ports). If the policies are only applied at the VLAN level, they may not block rogue traffic effectively.
- Switch Model and Software Version: Some switch models and software versions have limitations or bugs that affect the effectiveness of RA Guard and DHCP Guard. Ensure that your switch supports these features fully and that you are running the latest stable software version.
3. Recommendations
To address the issue, consider the following steps:
a. Apply Policies at the Interface Level
Instead of applying RA Guard and DHCP Guard policies at the VLAN level, apply them directly to the access interfaces where end-user devices are connected. For example:
interface GigabitEthernet1/0/1
switchport mode access
switchport access vlan 20
ipv6 nd raguard attach-policy DHCP-HOST
ipv6 dhcp guard attach-policy DHCP-CLIENT
Repeat this configuration for all access interfaces.
b. Verify Policy Effectiveness
After applying the policies, verify that they are active and functioning as expected. Use the following commands to check the status:
show ipv6 nd raguard policy
show ipv6 dhcp guard policy
c. Enable IPv6 Snooping
Some switches support IPv6 snooping, which can enhance the effectiveness of RA Guard and DHCP Guard. Enable IPv6 snooping on the relevant VLANs:
ipv6 snooping
ipv6 snooping vlan 20
ipv6 snooping vlan 41
ipv6 snooping vlan 50
ipv6 snooping vlan 51
d. Update Switch Software
Ensure that your switches are running the latest stable software version. Check the release notes for any known issues or enhancements related to RA Guard and DHCP Guard.
e. Disable Unused IPv6 Features
If your organization does not use IPv6, consider disabling IPv6 on access interfaces to eliminate the attack surface. For example:
interface GigabitEthernet1/0/1
Alternatively, you can globally disable IPv6 on the switch if it is not needed:
f. Monitor and Test
After implementing the changes, monitor the network for any unauthorized IPv6 activity. Conduct additional penetration testing to verify that the configuration is effective.
4. Conclusion
The issue likely stems from the policies being applied at the VLAN level rather than the interface level, or from limitations in the switch's implementation of RA Guard and DHCP Guard. By applying the policies at the interface level, enabling IPv6 snooping, and ensuring that your switches are running the latest software, you can improve the effectiveness of your defenses against IPv6 attacks.
If your organization does not use IPv6, disabling IPv6 entirely on access interfaces or globally is the most effective way to prevent such attacks.
Hope This Helps!!!
AshSe
Community Etiquette:
- Insert photos/images inline - don't attach.
- Always mark helpful and correct answers, it helps others find what they need.
- For a prompt reply, kindly tag @name. An email will be automatically sent to the member.
