bugtraq - Re: Dropbear SSH server Denial of Service

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Date: Sat, 11 Mar 2006 13:51:47 +1100 (EST)
From: Damien Miller <djm@...drot.org>
To: Matt Johnston <matt@....asn.au>
Cc: full-disclosure@...ts.grok.org.uk, bugtraq@...urityfocus.com,
	Pablo Fernandez <pablo@...tleQ.net>
Subject: Re: Dropbear SSH server Denial of Service

On Fri, 10 Mar 2006, Matt Johnston wrote:

> Dropbear 0.48 mitigates this issue by having a per-IP limit
> as well as a global limit - this will at least prevent an
> IP-deprived attacker from denying service.
> 
> It's worth noting that various other network services (such
> as netkit-inetd and OpenSSH) have the same design issues, at
> least in default configurations.

OpenSSH has had connection-flood DoS mitigation since 2000, in the 
form of random early drop of connections so legitimate users have a
probabalistic change of getting in. See the "MaxStartups" documentation
in sshd_config(5)

-d

_______________________________________________
Full-Disclosure - We believe in it.
Charter: http://lists.grok.org.uk/full-disclosure-charter.html
Hosted and sponsored by Secunia - http://secunia.com/