PlaidCTF 2019

Can You Guess Me

Category: Misc

Posted on April 19, 2019

Prompt:

Here's the source to a guessing game: here You can access the server at

nc canyouguessme.pwni.ng 12349

Solution:

The program is vulnerable because the input is passed to
eval(...)
which is a common vulnerability. You can read up more on Ned Batchelder's eval really is dangerous The tricky thing is that the input is sanitized for only 10 distinct characters. Entering
print( vars( ) )
does the trick and the flag shows up.

Flag:

PCTF{hmm_so_you_were_Able_2_g0lf_it_down?_Here_have_a_flag}

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