Hard Live

Lost In The Binary

80 points

123 Solves

Reverse Engineering

Hard

ramza500

Community Rating: 4.82 / 5

I lost a flag inside this binary, please help me to find it. If you trigger certain anti-debugging techniques, you might get false flagsā€¦. flag format: FLAG-(str) https://mega.nz/#!ifgzQQCC!E1W0cSOFRvi7bE_v419rzwQB2jAHF0IsIRAWL6H1RNE

First 10 Solvers

Rank Username
1 vidar
2 blakeks4711
3 kronos
4 voidmercy
5 Yeraisci
Rank Username
6 getbackmazafaka
7 lunatic
8 slowr
9 lonelyboyz
10 kerrodali

  • b4el7d

    Some hint to trigger correct cmp (rdp-34h), 4?

    • EdbR

      Think about the arguments

    • sheng855174

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      • EdbR

        Look on disassembler you will find some conditions that will help you find the correct parameters. And the parameters are not in md5.

        • sheng855174

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          • EdbR

            You are very close !!! I passed the same way as you. You have the condition of "(rdp-34h), 4?" and as you know you need to pass 4 arguments. Now try to see in IDA where the flow goes if you passed 4 arguments. You will be see 4 if conditions that will helps you to generate 4 equation with 4 variable and by that you will find the correct arguments.

            • sheng855174

              I succeed!!! I am freshman, interested in information security. Thank you!

              • EdbR

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          • b4el7d

            Hello I had found another fake flag easy_f14g and using the if condition compose of 4 strtol and 4 equation i had found 4 value : 248.84050000000002 112.77770000000001 200.6176 309.4615

            but its so wrong. Can u help me to understand the method? TY

            • EdbR

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              • b4el7d

                SOLVED wrong linear equation. Ty for support!

                • EdbR

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  • domin568

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    • mavleop

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    • Rivit

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  • mavleop

    I liked the challenge, was annoying that I I had to have a specific version of openssl installed. Was quicker just to manually recover.

  • IT_Oracle

    Whew, I confused myself a lot on that one hahahaha. Thanks for the super fun challenge, it taught be a ton of new things!