Dangling DNS: Announcekit
Another service vulnerable to subdomain takeover
This post is the write-up about the subdomain takeover vulnerable service Announcekit that I found. Although this is a paid service, It's possible to create PoC without purchasing the service during the trial period.
AnnounceKit is a user communication platform that helps you announce product updates to increase feature adoption.
CNAME
record should be pointing to cname.announcekit.app
akit-tk.melbadry9.xyz. 42 IN CNAME cname.announcekit.app.
id: detect-announcekit
info:
name: Announcekit service detection
author: melbadry9
severity: info
tags: dns
dns:
- name: "{{FQDN}}"
type: CNAME
class: inet
recursion: true
retries: 2
matchers:
- type: word
words:
- "cname.announcekit.app"
We should see a similar error page to verify whether the subdomain takeover may be possible.

Vulnerable Subdomain Error Page
To detect a vulnerable subdomain, we use the following fingerprint based on the HTTP response. we confirm whether the subdomain is vulnerable or not.
{
"status_code": 404,
"text": [
"Error 404 - AnnounceKit"
]
}
id: announcekit-takeover
info:
name: Announcekit Takeover Detection
author: melbadry9
severity: high
tags: takeover
reference: https://announcekit.app/docs/custom-host
requests:
- method: GET
raw:
- |
GET / HTTP/2
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
redirects: true
max-redirects: 1
matchers-condition: and
matchers:
- type: word
words:
- 'Error 404 - AnnounceKit'
- type: status
status:
- 404
- Go to
https://announcekit.app/dashboard/settings/feeds
- Set
Custom Hostname
to the subdomain, we want to takeoverakit-tk.melbadry9.xyz

Takeover Steps
- Visit
https://kit-tk.melbadry9.xyz

PoC
Last modified 6mo ago