Bug#626112: openssh-server: ssh doesn't log some failed authentications to auth.log anymore

[Christoph Anton Mitterer <calestyo@scientia.net>]

Package: openssh-server
Version: 1:5.8p1-4
Severity: grave
Tags: security
Justification: user security hole


Hi.

For *some* failed connections ssh seems to put no logging into auth.log anymore.
This can be quite security relevant when using e.g. fail2ban which relies on this.

Only some (types?) of connections seem to be affected, as I still see few IPs
that get banned by fail2ban.

But when I e.g. go to another host of mine, and try repeatedly to login, they don't
get banned (as nothing appears in the logs).
I tried both, hosts where a ~/.ssh/id_rsa* was in place and not.


Attached is my sshd's configuration. Please ask for mor information if you need any.


Cheers,
Chris.



-- debconf information:
  ssh/vulnerable_host_keys:
  ssh/new_config: true
* ssh/use_old_init_script: true
  ssh/disable_cr_auth: false
  ssh/encrypted_host_key_but_no_keygen:

ListenAddress lo.localhost
ListenAddress lo.ip6-localhost
ListenAddress localhost.localhost
ListenAddress eth0.localhost
#ListenAddress eth0.ip6-localhost

AllowUsers root
#PermitRootLogin no

ChallengeResponseAuthentication no
PasswordAuthentication no
RSAAuthentication no

Protocol 2
Ciphers aes256-cbc,aes192-cbc,aes128-cbc,aes256-ctr,aes192-ctr,aes128-ctr,blowfish-cbc
MACs hmac-sha1,hmac-ripemd160

ClientAliveInterval 30
TCPKeepAlive no

AcceptEnv LANG LC_*
X11Forwarding yes

Subsystem sftp /usr/lib/openssh/sftp-server