CTF-MISC-图片隐写（持续更新）

1.像素隐写

题目来源--GDOUCTF

图片中含有异常的像素点，通常需要修改图片大小将其显现出来

这张图片放大后可以看到许多异常的橡素点，用010editor查看此图片，发现其尾部藏有提示

需要将图片缩小12倍，利用脚本将其跑出

from PIL import Image

img = Image.open('arcaea.png')
w = img.width
h = img.height
img_obj = Image.new("RGB",(w//12,h//12))

for x in range(w//12):
    for y in range(h//12):
        (r,g,b)=img.getpixel((x*12,y*12))
        img_obj.putpixel((x,y),(r,g,b))

img_obj.save('ok.png')

后得到另一张图片

 在kali中使用zsteg指令能得到flag--NSSCTF{J3st_2_cats_battling}

 2.文件尾密文

 附件是一张jpg图片，用010editor查看文件尾

 是一段乱码，有个乱码恢复的在线网站

乱码恢复 (mytju.com)

 解出来社会核心价值观码

 图片详细消息有提示是outguess隐写

 

 解出来得到另一个密文

 识别得decabit code

 解码得

3.IDAT块

 

考点：java盲水印、IDAT块隐写、base64隐写、jphs隐写

将附件的png图片进行java盲水印提取

 

得到一个压缩包的密码，解开得到另一张图片

使用pngcheck查看png图片的IDAT块是否异常

上一个IDAT块数据还未填满就出现下一个，可以知道这段IDAT数据块有问题

将其他IDAT块都删除并保存

隐约看到有字符，这里后来出题人给了提示需要爆破宽高（可惜了当时比赛时测试所有的提出的IDAT块图片唯独这一张没有爆破）

爆破宽高出一个密码

 

此密码为另一个jpg的压缩包密码 

提取数据并逆序输出

str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
bytes=bytes.fromhex(str[::-1])
output = open('flag.zip','wb')
output.write(bytes)

解密压缩包，得到一段base64文段，可以猜测是base64隐写

 

这段密钥是jphs的密钥

密码是m1ku_1s_sha_fufu123