Internet Protocols 1 3 Plz 1 (88.52 KiB) Viewed 59 times
Internet Protocols 1 3 Plz 2 (35.12 KiB) Viewed 59 times
1. (20 points) Protocol Perils In 2015, Github experienced a Denial of Service (DoS) attack orchestrated by China using the so-called "Great Cannon" (GC). It worked as follows. (Some details of the attack have been simplified or modified for this problem.) Many websites include a fetch for a script for analytics from Baidu, a large Inter- net service in China somewhat similar to Google. The script would be retrieved via: http://hm.baidu.com/h.js. The GC operated in-path at the border between China and the rest of the Internet. Upon see- ing a request for this script, the GC would prevent the original HTTP request from being forwarded, and would instead return a different script, which instructed clients to repeat- edly load http://github.com/cn-nytimes. You can assume that Baidu served its traffic using servers in China; Github did so from servers in the USA; and websites using the analytics script were hosted all over the world. 1) (4 points) For which of the following layers would the GC need to guess or infer header values it could not directly determine in order to carry out the attack? Check ALL that apply. a. Link b. Network c. Transport d. Application e. None of the above.
2) (4 points) Which layer was this attack meant to particularly stress regarding Github's servers? Mark the BEST choice. a. Physical b. Link c. Network d. Transport e. Application 3) (4 points) Whose traffic contributed to the DDOS attack? Mark the BEST choice. a. Web browsers inside China b. Web browsers outside China c. Both of these d. Neither of these
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