[ctf show] [MISC] misc1~misc9 basic questions of image steganography

Image steganography in MISC generally hides the flag in the image file. This article first lists a few simple methods. If I have time later, I will write a summary of image steganography~

1. Introduction to steganography method:

1. Modify the file suffix name, for example: change jpg to txt, flag is hidden in the picture, see [misc4]
2. Hide the text in the binary file of the picture (including the combination of picture and txt file), see [misc5], [ misc6], [misc7] and [misc9]
3. Merge the picture and flag file (except txt format, it can be a picture or zip) into the picture, see [misc8]

2. Practice

The url of the topic: CTF show
The topic range: [misc1]~[misc9]

1. Topic 1 [misc1]: Open the picture to see the flag

misc1
Open the picture and use the [Screen Recognition] function in [QQ Screenshot] to get the answer [ctfshow{22f1fb91fc4169f1c9411ce632a0ed8d}]

2. Topic 2 [misc2]: Open the picture to see the flag

misc2
Open the picture and use the [Screen Recognition] function in [QQ Screenshot] to get the answer [ctfshow{6f66202f21ad22a2a19520cdd3f69e7b}]

3. Topic 3 [misc3]: a bpg picture

1). Go to the bpg official website to download the 64-bit viewer
windows64 bit viewing tool
2). Put misc3.bpg in the decompression directory of the bpg viewer downloaded in the first step, execute cmd in the current directory, and run [bpgview.exe misc3.bpg ], you can view picture
Answer
3). Use the screen recognition function of the qq screenshot. If the answer is wrong, pay attention to 0 and the letter o, 1 and the letter l, and correct it manually

4. Topic 4 [misc4]: Modify the suffix of the picture to txt

1). Open them one by one with winhex, and search for the file header in the file header logo collection.
2). The suffixes obtained are png, jpg, bmp, gif, tif, webp (if webp cannot be opened, open it with chrome browser) )
document

5. Topic 5 [misc5]: The flag is in the binary file

Open with winhex, pull to the bottom to see the flag at the beginning of ctfshow

6. Topic 6 [misc6]: The flag is in the binary file

Open it with winhex, press [ctrl] + [f], search for [ctfshow], you can see the flag at the beginning of ctfshow

7. Topic 7 [misc7]: The flag is in the binary file

Open it with winhex, press [ctrl] + [f], search for [ctfshow], you can see the flag at the beginning of ctfshow

8. Topic 8 [misc8]: The flag file is hidden in the picture

Separate the file with foremostlrb ( download address ), open the [00000007.png] file, and you can see the flag

9. Topic 9 [misc9]: The flag is in the binary file

Open it with winhex, press [ctrl] + [f], search for [ctfshow], you can see the flag at the beginning of ctfshow

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Origin blog.csdn.net/guggle15/article/details/122297424