(a) What is a dual-homed host? (b) What is (are) the potential vulnerabilities o
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Question
(a) What is a dual-homed host?
(b) What is (are) the potential vulnerabilities of a dual-homed host?
(c) How can it be fixed/mitigated?
2. We discussed various VLAN attacks and countermeasures in the class. Please refer to the reference section of the lecture note for more details. There are two basic approaches to implementing these countermeasures:
(a) Using insecure network management protocols such as SNMP, FTP, tenet, etc. or their secure variants of these proto- cols such as SSH, SCP, SSL, etc. (b) Using out-of-band management in which we put all the management VLAN into a dedicated non-standard VLAN where nothing but management traffic resides. Briefly discuss the pros and cons of implementing countermeasures using in-band or out-of-band communications with respect to
i) efficiency, and
ii) securing security implementations, i.e., preventing attacks on countermeasures, and
iii) cost. For example using the same protocol for both traffic and monitoring (i.e., various IP packets), or a completely different protocol that may use different paths.
3. Make a summary table of all L2 vulnerabilities you have learned so far, the table must include attack type (which protocol), severity of the attack (in terms of eavesdropping, or misconfiguring), countermeasure for The attack, and effectiveness of the countermeasure. Something like; Attack Attack severity Countermeasur(s) Effectiveness CS
Explanation / Answer
(a) What is a dual-homed host?
A dual-homed host is a term used to reference a type of firewall that uses two (or more) network interfaces. One connection is an internal network and the second connection is to the Internet. A dual-homed host works as a simple firewall provided there is no direct IP traffic between the Internet and the internal network.
An example of dual-homed devices are enthusiast computing motherboards that incorporate dual Ethernet network interface cards.
(b) What is (are) the potential vulnerabilities of a dual-homed host?
Proxy services are effective only when they're used in conjunction with a mechanism that restricts direct communications between the internal and external hosts. Dual-homed hosts and packet filtering are two such mechanisms. If internal hosts are able to communicate directly with external hosts, there's no need for users to use proxy services, and so (in general) they won't. Such a bypass probably isn't in accordance with your security policy.
To implement a dual homed firewall, IP packets from one network (e.g., the Internet) are not directly routed to the other network (e.g., the internal, protected network). Systems inside the firewall can communicate with the dual-homed host, and systems outside the firewall (on the Internet) can communicate with the dual-homed host, but these systems can't communicate directly with each other. IP traffic between them is completely blocked.
A dual-homed host can only provide services by proxying them, or by having users log into the dual-homed host directly. User accounts present significant security problems by themselves. They present special problems on dual-homed hosts, where they may unexpectedly enable services you consider insecure. Furthermore, most users find it inconvenient to use a dual-homed host by logging into it.
(c) How can it be fixed/mitigated?
The screened subnet architecture offers some extra options for providing new and/or untrusted services (e.g., you can add to the screened subnet a worthless machine that provides only an untrusted service).
By using different architectures like interior router,Bastion host,exterior router. e.g. You can get significant increases in security by combining a dual-homed host architecture with a screened subnet architecture. To do this, split the perimeter network and insert a dual-homed host. The routers provide protection from forgery, and protect from failures where the dual-homed host starts to route traffic. The dual-homed host provides finer controls on the connections than packet filtering. This is a belt-and-suspenders firewall, providing excellent multilayered protection, although it requires careful configuration on the dual-homed host to be sure you're taking full advantage of the possibilities. (There's no point in running simple, straight-through proxies.)
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