Rating:
# Well Known
This task was part of the 'Web' category at the 2020 Hexion CTF (during 11-13 April 2020).
It was solved by [The Maccabees](https://ctftime.org/team/60231) team.
# The challenge
Description:
```
Well... it's known (:
https://wk.hexionteam.com
```
When entering the website, we get a 404 error code.
The challenge name and description indicates this has some connections to [RFC8615](https://tools.ietf.org/html/rfc8615) - which defines a path prefix in HTTP(S) URIs for these "well-known locations", "/.well-known/".
This wikipedia page lists all the possible well-known URIs: [List of /.well-known/ services offered by webservers](https://en.wikipedia.org/wiki/List_of_/.well-known/_services_offered_by_webservers).
So we just iterated over all of them in this python script:
```python
#!/usr/bin/env python
import requests
domain = "https://wk.hexionteam.com/.well-known/{}"
well_known_uris = [
"acme-challenge",
"ashrae",
"assetlinks.json",
"caldav",
"carddav",
"coap",
"core",
"csvm",
"dnt",
"dnt-policy.txt",
"est",
"genid",
"hoba",
"host-meta",
"host-meta.json",
"http-opportunistic",
"keybase.txt",
"mercure",
"mta-sts.txt",
"ni",
"openid-configuration",
"openorg",
"pki-validation",
"posh",
"reload-config",
"repute-template",
"resourcesync",
"security.txt",
"stun-key",
"time",
"timezone",
"uma2-configuration",
"void",
"webfinger",
"apple-app-site-association",
"apple-developer-merchantid-domain-association",
"browserid",
"openpgpkey",
"autoconfig/mail",
"change-password",
"nodeinfo", ]
for well_known_uri in well_known_uris:
d = domain.format(well_known_uri)
r = requests.get(d)
if r.status_code != 404:
print(well_known_uri)
```
The script returned two results:
```
http-opportunistic
security.txt
```
When browsing to the `security.txt` URI, we get the flag!
```
Flag: hexCTF{th4nk_y0u_liv3_0v3rfl0w}
```
