Create Lab 1.md

Portswigger/Insecure Deserialization/Lab 1.md

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+# Portswigger Insecure Deserialization - Lab 1
+
+## Modifying serialized objects
+
+In this lab we need to modify the session cookie which is using serlialization through which we need to escalate our privileges to administrator user and then delete the carlos user
+
+<img src="https://i.imgur.com/kaGspTX.png"/>
+
+We can login with the credentials `wiener:peter`
+
+<img src="https://i.imgur.com/dtALDtP.png"/>
+
+After logging in we'll see the session token
+
+<img src="https://i.imgur.com/3MbdElV.png"/>
+
+```
+Tzo0OiJVc2VyIjoyOntzOjg6InVzZXJuYW1lIjtzOjY6IndpZW5lciI7czo1OiJhZG1pbiI7YjowO30%3d
+```
+
+Which is base64 encoded, we can decode this, I used cyberchef
+
+<img src="https://i.imgur.com/MUd4vTf.png"/>
+
+Now to understand the serlized cookie 
+
+```
+O:4:"User":2:{s:8:"username";s:6:"wiener";s:5:"admin";b:0;}
+```
+
+- `O:4` represents that `User` is a object of length 4, which has 2 attributes which are username and admin
+- `username`  is a string of length `8`, which has the value `wiener` of length `6`
+- `admin` is a string with length `5` which has a boolean value which is represented by `b` having the value `0` which is false
+
+So we need to make this value true with `b:1`
+
+<img src="https://i.imgur.com/FDEpRNF.png"/>
+
+<img src="https://i.imgur.com/gghSrSP.png"/>
+
+After refreshing the page we'll see that we have access to admin panel
+
+<img src="https://i.imgur.com/4cubhe2.png"/>
+
+And we can delete carlos user and complete the lab
+
+<img src="https://i.imgur.com/W9kXxaY.png"/>
+