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Secure Portal

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Challenge | 2020 | CSICTF | Web | Secure Portal

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WriteUp来源

by anishbadhri

题目描述

This is a super secure portal with a really unusual HTML file. Try to login.

题目考点

解题思路

In the sourcecode, an unreadable script is at the end. The javascript code can be deobfuscated to an extent with http://www.jsnice.org/. The script still has a lot of useless functions. On replacing all necessary values into the corresponding locations, we get a final script of

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window["localStorage"]["setItem"]("9-12", "BE*");
window["localStorage"]["setItem"]("4-7", "bb=");
window["localStorage"]["setItem"]("0-2", "5W");
window["localStorage"]["setItem"]("16", "^7M");
window["localStorage"]["setItem"]("12-14", "pg");
window["localStorage"]["setItem"]("7-9", "+n");
window["localStorage"]["setItem"]("14-16", "4t");
window["localStorage"]["setItem"]("2-4", "$F");

From here, its clearly visible that that the password is just rearranging this into increasing order of key. On entering the password, the flag is obtained.

Password: 5W$Fbb=+nBE*pg4t^7M

Flag

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csictf{l3t_m3_c0nfus3_y0u}