Firewall Address Resolution Cache Spoofing Prevention
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Solution Overview
Problem
Address resolution caches in computer networks are vulnerable to spoofing attacks, where malicious entities can forge MAC addresses, intercepting communications and disrupting data flow, which existing protocols like ARP and IPv6 neighbor discovery protocols fail to effectively prevent.
Innovation Solution
A firewall system that maintains a shadow copy of the address resolution cache with a longer residency lifetime, checks for discrepancies in address resolution messages, and verifies the authenticity of unsolicited messages by requesting network elements to confirm their address resolution information, thereby identifying and preventing spoofed messages from updating the cache.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ARP cache automatically updates with received address resolution responses, then address resolution efficiency is improved, but vulnerability to spoofing attacks increases
Solution Approach 1:
The system performs preliminary verification of address resolution responses before updating the ARP cache. It checks whether the source MAC address in the response matches the expected MAC address obtained through unicast ARP requests, preventing spoofed entries from being cached before they can cause harm.
Solution Approach 2:
The system introduces an intermediary verification mechanism between receiving ARP responses and updating the cache. This intermediary layer validates the authenticity of address resolution information by comparing it with independently obtained data, acting as a mediator that filters out malicious spoofed responses.
2Reliability
If ARP cache entries are periodically flushed, then obsolete information is eliminated, but address resolution time increases
Solution Approach 1:
The system applies different retention policies to different cache entries based on their verification status. Verified and authenticated address resolution entries maintain longer residency times, while unverified or suspicious entries are flushed more quickly, creating localized quality differences in cache management.
Solution Approach 2:
The cache residency time becomes dynamic rather than static. Entries undergo verification processes that can extend their lifetime if authenticated, while failing entries are quickly removed. This dynamic adjustment optimizes both reliability and resolution time based on actual entry validity.
3Adaptability or versatility
If unsolicited ARP replies are accepted, then network protocol compatibility is maintained, but security against cache poisoning is compromised
Solution Approach 1:
The system implements preliminary anti-action by proactively sending unicast ARP requests to verify the authenticity of unsolicited ARP replies before accepting them. This preemptive verification prevents cache poisoning while still allowing legitimate unsolicited replies to be processed, maintaining protocol compatibility without compromising security.
Solution Approach 2:
The system introduces feedback verification where unsolicited ARP replies are not immediately accepted but are instead validated through a feedback loop involving unicast ARP requests. The reply is only accepted if it matches the response from the verification request, ensuring cache integrity while maintaining protocol compatibility.
Data Source
AI summary
A firewall identifies unsolicited messages having an address resolution for a network protocol address different than cached address resolution information. The accuracy of the unsolicited messages is checked by requesting network elements to report address resolution information for the network protocol address.