Date: Fri, 2 Sep 2016 15:52:06 +1000 (AEST) From: Damien Miller <djm@...drot.org> To: oss-security@...ts.openwall.com cc: Solar Designer <solar@...nwall.com> Subject: Re: CVE request - OpenSSH 6.9 PAM privilege separation vulnerabilities On Thu, 13 Aug 2015, Moritz Jodeit wrote: > On 12.08.2015 22:48, Solar Designer wrote: > > Thank you! > > > > Are systems with "keyboard interactive" and "challenge-response" > > authentication disabled (all of PAMAuthenticationViaKbdInt, > > KbdInteractiveAuthentication, and ChallengeResponseAuthentication, as > > applicable to a given sshd version, set to no) affected by these issues > > as well? The code appears to be specific to this mode, but it isn't > > immediately clear whether or not these configuration settings prevent > > the vulnerable code from being reached in the privsep monitor even when > > the privsep child is compromised. If the settings do not currently > > prevent the code from being reached (I hope they do), then this should > > be corrected as a hardening measure. > > As long as UsePAM is enabled in the configuration, all the PAM-related > monitor requests can be send to the monitor. This at least allows > triggering the use-after-free even if all the settings you mentioned > are set to "no". Not sure if a full authentication is possible in this > case though. Solar just reminded me of this branch of this old thread, prompting me to tighten up OpenSSH's privilege separation monitor process: https://anongit.mindrot.org/openssh.git/commit/?id=775f8a23f235 https://anongit.mindrot.org/openssh.git/commit/?id=7fd0ea8a1db4 https://anongit.mindrot.org/openssh.git/commit/?id=b38b95f5bcc5 (there'll be another one for GSSAPI once I can find someone to test it) Together these more rigorously and explicitly enforce the expected request flow in the monitor process. Thanks for the reminder :) -d
Powered by blists - more mailing lists
Please check out the Open Source Software Security Wiki, which is counterpart to this mailing list.
Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.