Re: Probable SSH Vulnerability
On Fri, Jun 13, 2003 at 05:15:28PM -0400, David B Harris wrote:
> (This version of the message sent to you personally in the off chance
> that you're not subscribed to debian-security@lists.debian.org; sorry
> for not doing it via Cc:, but I forgot.)
>
> On Fri, 13 Jun 2003 14:18:44 -0400
> Tim Peeler <thp@linux00.LinuxForce.net> wrote:
> > In the last 4-5 days we have had 8 servers come under attack. We are
> > working frantically to keep ahead of these attacks. We have come to the
> > conclusion that the SSH in woody is likely vulnerable. Of the 8 servers
> > that have been broken into, half of them are running 2.2.20 and half
> > are running 2.4.18. We have been updating all servers to 2.4.21-rc8.
> > We are ruling out a kernel exploit because of this. Of the servers
> > attacked, one was only running sshd (from woody). We have not had time
> > to analyze where the exploit occurs in sshd, but we are very confident
> > that this is the location of the exploit. We have begun upgrading to
> > a backport of the testing version of ssh which appears to be helping.
>
> Could you provide your /etc/ssh/sshd_config, the version of your "ssh"
> package, and the output from 'debsums ssh'? Thanks.
>
sshd_config for comprimized server attached, as well as the output of
debsums ssh
SSH Version: 3.4p1-1
Just for information, these failed the global check:
bin/cp FAILED
bin/dd FAILED
bin/df FAILED
bin/dir FAILED
bin/ln FAILED
bin/ls FAILED
bin/mv FAILED
bin/rm FAILED
bin/su FAILED
bin/ping FAILED
bin/ps FAILED
bin/kill FAILED
bin/date FAILED
bin/echo FAILED
bin/pwd FAILED
bin/tar FAILED
bin/tcsh FAILED
bin/cat FAILED
# Package generated configuration file
# See the sshd(8) manpage for defails
# What ports, IPs and protocols we listen for
Port 22
# Use these options to restrict which interfaces/protocols sshd will bind to
#ListenAddress ::
#ListenAddress 0.0.0.0
Protocol 2,1
# HostKeys for protocol version 1
HostKey /etc/ssh/ssh_host_key
# HostKeys for protocol version 2
HostKey /etc/ssh/ssh_host_rsa_key
HostKey /etc/ssh/ssh_host_dsa_key
# Lifetime and size of ephemeral version 1 server key
KeyRegenerationInterval 3600
ServerKeyBits 768
# Logging
SyslogFacility AUTH
LogLevel INFO
# Authentication:
LoginGraceTime 600
PermitRootLogin yes
StrictModes yes
RSAAuthentication yes
PubkeyAuthentication yes
#AuthorizedKeysFile %h/.ssh/authorized_keys
# rhosts authentication should not be used
RhostsAuthentication no
# Don't read the user's ~/.rhosts and ~/.shosts files
IgnoreRhosts yes
# For this to work you will also need host keys in /etc/ssh_known_hosts
RhostsRSAAuthentication no
# similar for protocol version 2
HostbasedAuthentication no
# Uncomment if you don't trust ~/.ssh/known_hosts for RhostsRSAAuthentication
#IgnoreUserKnownHosts yes
# To enable empty passwords, change to yes (NOT RECOMMENDED)
PermitEmptyPasswords no
# Uncomment to disable s/key passwords
#ChallengeResponseAuthentication no
# To disable tunneled clear text passwords, change to no here!
PasswordAuthentication yes
# Use PAM authentication via keyboard-interactive so PAM modules can
# properly interface with the user
PAMAuthenticationViaKbdInt yes
# To change Kerberos options
#KerberosAuthentication no
#KerberosOrLocalPasswd yes
#AFSTokenPassing no
#KerberosTicketCleanup no
# Kerberos TGT Passing does only work with the AFS kaserver
#KerberosTgtPassing yes
X11Forwarding no
X11DisplayOffset 10
PrintMotd no
#PrintLastLog no
KeepAlive yes
#UseLogin no
#MaxStartups 10:30:60
#Banner /etc/issue.net
#ReverseMappingCheck yes
Subsystem sftp /usr/lib/sftp-server
#UsePrivilegeSeparation yes
AllowUsers root cjf linforce afradm afrjradm ave dave
usr/bin/ssh OK
usr/bin/scp OK
usr/bin/ssh-add OK
usr/bin/ssh-agent OK
usr/bin/ssh-keygen OK
usr/bin/ssh-keyscan OK
usr/bin/sftp OK
usr/bin/ssh-copy-id OK
usr/sbin/sshd OK
usr/lib/ssh-keysign OK
usr/lib/sftp-server OK
usr/share/man/man1/scp.1.gz OK
usr/share/man/man1/ssh-agent.1.gz OK
usr/share/man/man1/ssh-keygen.1.gz OK
usr/share/man/man1/ssh-keyscan.1.gz OK
usr/share/man/man1/sftp.1.gz OK
usr/share/man/man1/ssh-copy-id.1.gz OK
usr/share/man/man1/ssh.1.gz OK
usr/share/man/man1/ssh-add.1.gz OK
usr/share/man/man8/ssh-keysign.8.gz OK
usr/share/man/man8/sshd.8.gz OK
usr/share/man/man8/sftp-server.8.gz OK
usr/share/man/man5/ssh_config.5.gz OK
usr/share/man/man5/sshd_config.5.gz OK
usr/share/doc/ssh/README OK
usr/share/doc/ssh/changelog.gz OK
usr/share/doc/ssh/copyright OK
usr/share/doc/ssh/RFC.gz OK
usr/share/doc/ssh/OVERVIEW.gz OK
usr/share/doc/ssh/README.Debian.gz OK
usr/share/doc/ssh/changelog.Debian.gz OK
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