Bug#929684: agent forwarding should be disabled by default
Package: openssh-server
Version: 1:7.9p1-10
Severity: wishlist
There was a major security breach on the matrix.org servers, and they
have posted a lenghty postmortem:
https://matrix.org/blog/2019/05/08/post-mortem-and-remediations-for-apr-11-security-incident#ssh-agent-forwarding-should-be-disabled
In there they specifically make this recommendation:
> We’d like to recommend that packages of openssh start having
> secure-by-default configurations, as a number of the old options
> just don’t need to exist on most newly provisioned machines.
They are specifically refering to `AllowAgentForwarding` which
defaults to `yes` upstream and is unchanged in Debian.
I would like to suggest we take that recommendation into consideration
and disable Agent Forwarding by default, on all SSH client and servers
managed by Debian packages. I would similarly recommend disabling X11
forwarding, especially considering we're going to switch to Wayland
either in buster or bullseye.
A.
-- System Information:
Debian Release: 10.0
APT prefers testing
APT policy: (500, 'testing'), (1, 'unstable')
Architecture: amd64 (x86_64)
Kernel: Linux 4.19.0-5-amd64 (SMP w/4 CPU cores)
Locale: LANG=fr_CA.UTF-8, LC_CTYPE=fr_CA.UTF-8 (charmap=UTF-8), LANGUAGE=fr_CA.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled
Versions of packages openssh-server depends on:
ii adduser 3.118
ii debconf [debconf-2.0] 1.5.71
ii dpkg 1.19.6
ii libaudit1 1:2.8.4-3
ii libc6 2.28-10
ii libcom-err2 1.44.5-1
ii libgssapi-krb5-2 1.17-2
ii libkrb5-3 1.17-2
ii libpam-modules 1.3.1-5
ii libpam-runtime 1.3.1-5
ii libpam0g 1.3.1-5
ii libselinux1 2.8-1+b1
ii libssl1.1 1.1.1b-2
ii libsystemd0 241-3
ii libwrap0 7.6.q-28
ii lsb-base 10.2019051400
ii openssh-client 1:7.9p1-10
ii openssh-sftp-server 1:7.9p1-10
ii procps 2:3.3.15-2
ii ucf 3.0038+nmu1
ii zlib1g 1:1.2.11.dfsg-1
Versions of packages openssh-server recommends:
ii libpam-systemd 241-3
ii ncurses-term 6.1+20181013-2
ii xauth 1:1.0.10-1
Versions of packages openssh-server suggests:
pn molly-guard <none>
ii monkeysphere 0.43-3
pn rssh <none>
ii ssh-askpass 1:1.2.4.1-10
pn ufw <none>
-- debconf information excluded
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