A picture recognition text website protocol analysis

sample

URL click here
is relatively simple, no encryption parameters, suitable for beginners to practice

Start reverse analysis

grab bag

Fiddler packet capture

analyze

In reverse, look at the parameters required for the final processing request. Generally, the headers and body need to focus on
the process. It looks like the processing result. Go in and have a look.

The return value is exactly our image recognition result. There are 2 unknown parameters in the request, X-CSRF-TOKEN and keys, let's look for it in the previous request.

You can see that the keys are in the returned result of the upload image request. X-CSRF-TOKEN has not been seen yet.

This request has an additional token parameter, and other parameters are known.
Search for the value of token 45b6f412e47f51e4ebeb9dc51c655d74 and the value of X-CSRF-TOKEN, both of which are found in the first request.


So far, all parameters have been analyzed, and the summary steps are as follows

1. Get up_token, csrf-token
2. Upload the image through the parameter up_token to get the image key
3. Get the picture and return the result through the picture key and csrf-token

Fiddler issue log

0x80090302

Win32 (SChannel) Native Error Code: 0x80090302