Misc (eternal night), the preliminary competition of the innovation practice competition of the National College Students' information security competition

The tense final is finally over , I just have time to sum up one of the competitions some time ago misc subject , Layers of dolls are very interesting .

Title Attachment ：

link ：https://pan.baidu.com/s/1lZ6YCyyY3hdMx2_ymLlsyA 
Extraction code ：viy2 
-- From Baidu network disk super member V1 The share of

Get the picture , The old rules use 010 Open file ：

  A string of abnormal data is found at the end of the file   

Question prompt this question is lsb Steganography

Use the tool to analyze the color trace of the picture

 

In this color channel, I found a string of things similar to moss code

Analyze the file corresponding to the color track and find this string of ciphertext

  The title also suggests a little use password Of lsb Steganography , Associated with the github Last project cloacked-pixel

Project address ：GitHub - livz/cloacked-pixel: LSB steganography and detection

utilize a2 The information in the channel is read out, and the hidden information is output as a txt file

open txt file

 

 pk The file header   Obviously compressed package     Change the suffix of the file to zip  Prompt for password

At this time, we think of the last string of data in the picture at the beginning   Try various decryption methods   Last use md5 figure out

Get the final decompression password

decompression Get a picture

 

Unable to open   The prompt file is corrupt   

The conventional thinking here is based on crc Explode the correct width and height of the picture , Let the picture parse normally . Here is a more ingenious way

Change the picture name to flag.data  Reuse gimp Open the picture Adjust the width to get the final flag