EC week Review

Rules of Engagement Teams selected by instructor Host will read the entire questions. Only after, a team may “buzz” by raise of hand A team must answer the question within 5 seconds after buzzing in (must have answer at hand) If the answer is incorrect, the team will lose its turn and another team may buzz in. No score will be deducted. No negative scores. Maximum score is 100. Once reached, that team will stand down for others to participate. Teams will earn all points scored at the end of game. When selecting a question, Teams must only select questions of different value, unless there are no others, but may be from different categories. All team members will participate and will answer questions Only one round - No Daily Doubles, Double Jeopardy or Final Jeopardy … and no partial credits!

Jeopardy! TCP/IP Model EthernetInternet Protocol ARPRouting / MITM Privileges / Buffer Overflow BGP / BGP Routing 10 pts 20 pts 40 pts 60 pts 10 pts 10 pts 10 pts 10 pts 10 pts 10 pts 10 pts 10 pts 10 pts 10 pts 10 pts 10 pts 10 pts 10 pts 10 pts 10 pts 10 pts 10 pts 10 pts 10 pts 10 pts 10 pts 10 pts 10 pts 20 pts 20 pts 20 pts 20 pts 20 pts 20 pts 20 pts 20 pts 20 pts 20 pts 20 pts 20 pts 20 pts 20 pts 20 pts 20 pts 20 pts 20 pts 20 pts 20 pts 20 pts 20 pts 20 pts 20 pts 40 pts 40 pts 40 pts 40 pts 40 pts 40 pts 40 pts 40 pts 40 pts 40 pts 40 pts 40 pts 40 pts 40 pts 40 pts 40 pts 40 pts 40 pts 40 pts 40 pts 40 pts 40 pts 40 pts 40 pts 60 pts 60 pts 60 pts 60 pts 60 pts 60 pts 60 pts 60 pts 60 pts 60 pts 60 pts 60 pts 60 pts 60 pts 60 pts 60 pts 60 pts 60 pts 60 pts 60 pts 60 pts 60 pts 60 pts 60 pts 10 pts 10 pts 10 pts 10 pts 20 pts 20 pts 20 pts 20 pts 40 pts 40 pts 40 pts 40 pts 60 pts 60 pts 60 pts 60 pts

Which TCP/IP layer is responsible for processes that provide services to HTTP or FTP? TCP/IP 10 pts Application Layer

How many bytes are in a physical address? Ethernet 10 pts 6 Bytes Example F2 : 45 : 17 : FF : 71 : A2

Which of the following is not a valid IP address? (a) (b) (c) (d) Internet Protocol 10 pts Maximum octet value = 255

Which two layers does the Address Resolution Protocol (ARP) involve? ARP 10 pts Layer 2 (Data Link) & Layer 3 (Network)

Routing tables are maintained on which of the following: (a) routers (b) host computers (c) both a & b (d) neither Routing Tables 10 pts

TRUE/FALSE: It is best to order the routing table by decreasing mask value. Routing/MITM 10 pts True! This is “longest mask matching” principle

What does the Linux command sudo do? Privileges/Buffer Overflow 10 pts Executes a single command as the root user!

The Transport layer is encapsulated by which layer? TCP/IP 20 pts Network Layer (Layer 3)

What is the purpose of the CRC field in an Ethernet frame? Ethernet 20 pts Used for Error Detection

What is the network address for the IP address / 23 ? Internet Protocol 20 pts (Host bits)(Network bits) Zero out the host bits to get… (mask) (IP address) (Network ID) (Mask)

An evil attacker launching an ARP-spoof attempts to associate his ___________ address with the victim’s ___________ address. Answer choices: hardware or IP ARP 20 pts hardware IP

Routing/MITM 20 pts If a router receives a packet with a destination IP address that does not match any of the networks on the routing table, what does the router do with it? The router sends it to the default router. This is often indicated in the routing table by: MaskNetworkAny or /

Privileges/Buffer Overflow 20 pts What does setting the setuid permission on an executable program do? Whenever the program is executed it will behave as though it were being executed by the owner!

TCP/IP 40 pts What is the name of the collection of 1’s and 0’s at layers 5 through 2? Layer 5 – “Message” Layer 4 – “Segment” Layer 3 – “Packet or Datagram” Layer 2 – “Frame”

Calculate the bandwidth seen by user 3 if each network is connected via 10 Mbps Ethernet. Ethernet 40 pts B1B2 10Mbps ÷ 3 = 3.33Mbps

How many addresses can be assigned to hosts on the network / 26 ? Internet Protocol 40 pts 32 total bits – 26 network bits = 6 host bits =62 addresses assignable to hosts. Account for the broadcast and network addresses.

What two types of ARP messages exist? What is the fundamental problem with ARP that allows an ARP-spoof to be possible? ARP 40 pts ARP Request & ARP Reply An ARP reply can be sent (and be accepted!) without an ARP request

Routing/MITM 40 pts Fill in the missing information in the routing table for R1.

Privileges/Buffer Overflow 40 pts What is the correct order for arranging the payload in a buffer overflow attack, and what are their purposes? Choices are given below: The exploit (shellcode) Repeated return addresses NOP sled NOP Sled – It is a series of “no operation” commands that lets the hacker be a bit off with the return address, so that the return address just has to point anywhere within the NOP sled. Otherwise, the return address would need to be the precise first address of the exploit. The exploit – This is the executable program. Repeated return addresses – The return address points towards the exploit as the next instruction (however, see the note regarding the NOP sled). It is repeated so that the hacker would have a number of chances to get the address correctly positioned in the Return Address field in the stack.

Suppose an application entity wants to send a 100 byte message to a peer entity. If each layer from 4-2 appends a 15 byte header, what percentage of the total frame size is actual application entity data? TCP/IP 60 pts [100 / ( ) ] x100 = 69%

Ethernet 60 pts Assume the Network layer passes the Data Link layer 6030 bytes of information to transmit. How many Ethernet frames will be required? 6030÷1500 = 4.02 thus 5 Frames

What is the block of addresses assigned to the network / 23 ? Internet Protocol 60 pts (Network bits) (Host bits) = (First Address) = (Last Address) (mask)...

N1 : L1 N2 : L2 N3 : L3 N4 : L4 N5 : L5 You are user C in the network below. Design an ARP Spoofing attack on User D. What changes would you make to the ARP cache? ARP 60 pts L3

Routing/MITM 60 pts Design an MITM attack to divert traffic from the server Target’s Network Target’s IP Address Attacker’s Lie Ans: / 27 Other possible Answers: / / / / 31 Target’s Network Target’s IP Address Attacker’s Lie

Name and describe two technical solutions to prevent a buffer overflow attack. Privileges/Buffer Overflow 60 pts The non-executable stack: The CPU will not execute any machine instructions located in the portion of main memory reserved for the stack. The stack canary: The CPU checks a known value in memory just prior to the location of the return address (to make sure it was not changed) before resetting the EIP. Address space layout randomization: The stack and the heap are placed in random memory locations, preventing the hacker from easily predicting return addresses’ location.

Briefly describe each of the following Autonomous Systems Categories: (a) Stub AS (b) Multihomed AS (c) Transit AS BGP/BGP Routing 10 pts -Has only one connection to another AS -Has more than one connection to other ASes, but doesn’t allow data to pass through it -Connects to more than one AS and allows traffic to pass through it

Describe the steps followed in BGP routing when selecting a route. BGP/BGP Routing 20 pts 1)a BGP router first attempts to find all paths from the router to a given destination 2)it then judges these paths against the policies of the AS administrator 3)it then selects a “good enough” path to the destination that satisfies the policy constraints

BGP/BGP Routing 40 pts What AS path would an IP packet from take to reach ? What AS path would an IP packet from take reach ? What AS path would an IP packet from take to reach ? 40 – 2003 – – 40 – 2003 – 2005 Consider the network diagram and BGP route announcement from Router 3 below, assuming no local preferences are set.

Name and describe (include negative and positive consequences) one technical solution that an AS network operator can use to combat prefix hijacking an MITM attack on BGP networks? BGP/BGP Routing 60 pts Filtering – Best current practices for AS network operators dictate the use of filters at AS borders to reject suspicious route announcements or alter malicious route attributes. Filters are manually established based on the routing policies of an organization. Filtering has both a business cost and computational cost associated with it. Internet Routing Registries – These are repositories of the IP prefixes, ASNs, routing policy, network topology, and human points of contact for those ASes which choose to register their information. While this method may be effective, the downside is that these registries are only effective if the registry data is secure, complete, and accurate, which is currently not guaranteed. Resource Public Key Infrastructure (RPKI) – Similar to the IRRs, RPKI is a repository of Internet routing information. The key difference is that it uses the X.509 certificate system to provide cryptographic assurance of (1) the association between an ASN and the IP prefixes it has been allocated, and (2) the association between an ASN and the IP prefixes it is authorized to originate.  There is nothing in RPKI which validates the route attributes, including the AS path, associated with a BGP route announcement from an AS.  Nor does it provide certainty that the AS which has registered their information used the correct ASN or set of prefixes.  Nor does it provide network topology information or human points of contact as with IRRs.  Lastly, it does not mandate that network operators use this information when constructing their filters.  How RPKI is applied is entirely dependent on what AS network operators choose to do with the information available.

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