Susan Landau

Description

Susan Landau (born 1954) is an American mathematician, engineer, cybersecurity policy expert, and Bridge Professor in Cybersecurity and Policy at the Fletcher School of Law and Diplomacy at Tufts University. She previously worked as a Senior Staff Privacy Analyst at Google. She was a Guggenheim Fellow and a visiting scholar at the Computer Science Department, Harvard University in 2012. - Wikipedia Entry

Chal: Connect to our webserver and understand the concerns of this mathematician and privacy expert.

Challenge link

URL

Solution

  • On the landing webpage, clicking on Start Exploring, choosing a username, and then choosing any path leads us to a dead end.

  • But 2 cookies named csrf_token and PHPSESSID are set.

  • The clue in /sorry.html page mentions well-known cryptographic technique sorry

  • So we can crack csrf_token value using crackstation.net

  • 40c331964b7560a4d3baaae420d5e3cd md5 decrypt decodes to : hack this

  • We get a hint that we should play around with the csrf_token value.

  • In the login page, we have a hint username hint

  • Choosing cyberheroine as username.

  • Replace the csrf_token with the MD5 hash of cyberheroine.

  • Calculating the MD5 sum of cyberheroine

$ echo -n "cyberheroine" | md5sum                                
09a206b401aaa7b5315e1d814ce16896  -

  • md5(cyberheroine): 09a206b401aaa7b5315e1d814ce16896

  • Intercept the request using burpsuite and modifying the csrf_token cookie value.

burp

  • We get the flag.

flag

FLAG

chctf{U_a53_$ucc3$$ful!!!}

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