Task:
Hi, packet inspector,
the AI has "upgraded" our packet auditing system – time to time, it generates archive of pictures, where the state of packet and the appropriate delivery team is indicated by different colours for each packet transport number.
We have a plea from Brenda's delivery team to find their missing packet in state ready for pickup (the other teams have already delivered all their packages mentioned in last given audit archive).
Download audit archive (MD5 checksum 08ee155d2c9aee13ea5cab0a11196129), find the desired pickup code and enter it on webpage http://pickup.mysterious-delivery.thecatch.cz to collect pickup code.
--------------
We know from description.png that Brenda's color is orange, and Ready for pickup is green. I've got the accurate RGB values from it, and using this code find the corresponding image:
static void Main(string[] args)
{
string[] allfiles = Directory.GetFiles(".", "*.png", SearchOption.AllDirectories);
for (int i = 0; i < allfiles.Length; i++)
{
//Console.WriteLine(allfiles[i]);
//Color [A=255, R=242, G=121, B=48]
//Color [A=255, R=0, G=133, B=71]
Bitmap im = new Bitmap(allfiles[i]);
if (im.GetPixel(20, 20).Equals(Color.FromArgb(255, 242, 121, 48)))
{
if (im.GetPixel(100, 100).Equals(Color.FromArgb(255, 0, 133, 71)))
{
Console.WriteLine(allfiles[i]);
}
}
}
}
Using this code, I've got file 2022-08\30\19\000000.png, that contained code 629-367-219-835 and after entering this code to the page mention in the task, you get flag:
FLAG{rNM8-Aa5G-dF5y-6LqY}