Suppose you have a simple host running Virtualbox with NAT networking and do malware testing on it, how safe are you?

So, just a single windows host attached to the router and a virtual machine running on it. No shared folders or clipboard. Just testing your average malware.

Note that this question talks about just a single PC connected to a router, without any fancy file sharing enabled via network (It can have stuff like torrents and download managers, but not anything like a shared folder in the network).

networking restart fails (Failed to start Raise Network Interfaces), networking ignores static ip address

So I have a linux server running ubuntu. I set this thing up a while ago and setup a static IP and everything has been fine, up until now. Today, there was a power surge at my house and the server is now using the wrong IP address, is ignoring the /etc/network/interfaces file, and I can’t restart networking.

ifconfig

ifconfig enp3s0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500         inet 192.168.1.8  netmask 255.255.255.0  broadcast 192.168.1.255         inet6 fe80::a250:98ca:d9cc:188  prefixlen 64  scopeid 0x20<link>         ether 30:85:a9:8d:fa:d5  txqueuelen 1000  (Ethernet)         RX packets 815  bytes 731980 (731.9 KB)         RX errors 0  dropped 0  overruns 0  frame 0         TX packets 695  bytes 86443 (86.4 KB)         TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0  lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536         inet 127.0.0.1  netmask 255.0.0.0         inet6 ::1  prefixlen 128  scopeid 0x10<host>         loop  txqueuelen 1000  (Local Loopback)         RX packets 255  bytes 21586 (21.5 KB)         RX errors 0  dropped 0  overruns 0  frame 0         TX packets 255  bytes 21586 (21.5 KB)         TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0 

Interfaces file

 cat /etc/network/interfaces # interfaces(5) file used by ifup(8) and ifdown(8) auto enp3s0 iface enp3s0 inet dhcp  auto lo enp3s0 iface lo inet loopback iface enp3s0 inet static         address 192.168.1.7         netmask 255.255.255.0         gateway 192.168.1.1         dns-nameservers 75.75.75.75 75.75.76.76 

Resolves to two hostnames (which doesn’t make sense to me)

hostname -I 192.168.1.8 192.168.1.7 

Network restart failure

 sudo /etc/init.d/networking restart [....] Restarting networking (via systemctl): networking.serviceJob for networking.service failed because the control process exited with error code. See "systemctl status networking.service" and "journalctl -xe" for details.  failed! 

systemctl status networking.service

 systemctl status networking.service ● networking.service - Raise network interfaces    Loaded: loaded (/lib/systemd/system/networking.service; enabled; vendor preset: enabled)    Active: failed (Result: exit-code) since Fri 2019-08-09 22:05:47 MDT; 25s ago      Docs: man:interfaces(5)   Process: 2137 ExecStart=/sbin/ifup -a --read-environment (code=exited, status=1/FAILURE)  Main PID: 2137 (code=exited, status=1/FAILURE)  Aug 09 22:05:46 SilverServer dhclient[2160]: DHCPACK of 192.168.1.8 from 192.168.1.1 (xid=0x7b2bf54d) Aug 09 22:05:46 SilverServer ifup[2137]: DHCPACK of 192.168.1.8 from 192.168.1.1 (xid=0x7b2bf54d) Aug 09 22:05:46 SilverServer ifup[2137]: RTNETLINK answers: File exists Aug 09 22:05:47 SilverServer dhclient[2160]: bound to 192.168.1.8 -- renewal in 37852 seconds. Aug 09 22:05:47 SilverServer ifup[2137]: bound to 192.168.1.8 -- renewal in 37852 seconds. Aug 09 22:05:47 SilverServer ifup[2137]: RTNETLINK answers: File exists Aug 09 22:05:47 SilverServer ifup[2137]: ifup: failed to bring up enp3s0 Aug 09 22:05:47 SilverServer systemd[1]: networking.service: Main process exited, code=exited, status=1/FAILURE Aug 09 22:05:47 SilverServer systemd[1]: networking.service: Failed with result 'exit-code'. Aug 09 22:05:47 SilverServer systemd[1]: Failed to start Raise network interfaces. 

I want the server to start up using 192.168.1.7, but I can only connect to it with putty through 192.168.1.8. I’ve been working on this problem for two hours now and have gotten nowhere. Please help, happy to clarify anything and happy to try anything.

Thanks!

Microsoft Azure Networking Rabbit Hole

I have been learning MS Azure for some weeks now but, despite extensive use of the internet, I am still confused about the Azure networking set up, and hence struggle to grasp how to configure my solution and -security properly.

Problem: I am unable to make out a comprehensive picture about how everything is linked, and WHY! E.g. I am not finding consistent definitions of ‘vnet’ or ‘subnet’; to my understanding a network is a nexus of nodes but then why is the Azure topology chart showing a subnet as a separate ‘node’? MS web pages state strange statements like “A virtual network rule for your SQL Database server is a subnet…” or “A Virtual Network service endpoint is a subnet…” just before (https://docs.microsoft.com/en-us/azure/sql-database/sql-database-vnet-service-endpoint-rule-overview?toc=%2fazure%2fvirtual-network%2ftoc.json).

I also was reading MS pages on “Azure Service Endpoints” but still cannot explain what they really are! I read fuzzy wording like “Virtual Network (VNet) service endpoints extend your virtual network private address space and the identity of your VNet to the Azure services…. Endpoints allow you to secure your critical Azure service resources to only your virtual networks…”, which seems containing confusing grammar errors (https://docs.microsoft.com/en-us/azure/virtual-network/virtual-network-service-endpoints-overview) – I just does not make sense out of this!

Could someone please give a high-level but precisely-worded overview on the ‘Why’ of the Azure networking topology setup, or a good internet link explaining this matter? I am lost deep in the rabbit hole with this, and need some light- without this I don’t like to enter the next rabbit hole called “Securing an Azure solution”…

Topology chart: Where are the “Azure Service Endpoints” SQL Server, Storage Account, Key Vault?

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My custom Docker image doesn’t have networking

this one’s a little bit odd but I may need some guidance on that.

I’ve created a custom image starting from maven:3.6-jdk-8, and the image seems to work just fine.

However, it’s like there’s no network in my container.

To see if it was an issue related to my machine, I did some tests with another container, and it works fine.

Here’s a little bit of output:

(working 3rd-party tool)

docker run -it --net host nicolaka/netshoot                     dP            dP                           dP                     88            88                           88 88d888b. .d8888b. d8888P .d8888b. 88d888b. .d8888b. .d8888b. d8888P 88'  `88 88ooood8   88   Y8ooooo. 88'  `88 88'  `88 88'  `88   88 88    88 88.  ...   88         88 88    88 88.  .88 88.  .88   88 dP    dP `88888P'   dP   `88888P' dP    dP `88888P' `88888P'   dP  Welcome to Netshoot! (github.com/nicolaka/netshoot) root @ /  [1] 🐳  → curl www.google.com <!doctype html><html itemscope="" itemtype="http://schema.org/WebPage" lang="it"><head><meta content="text/html; charset=UTF-8" http-equiv="Content-Type"><meta content="/lo... rest of google.com output 

(my non-working image)

docker run -it myimage/myimage /bin/bash root@eab59605cf95:/# curl www.google.com curl: (6) Could not resolve host: www.google.com 

Both containers have the very same contents in /etc/resolv.conf, and I really don’t know what to look for to solve this issue.

Networking Package for Unity design concerns

I wanted to float some design questions I had about a project I’m trying to build. I’m currently working on a package to allow any indie game developer to create a multi-player version of their game. I’m achieving arbitrary code by using Assembly.Load to load your Game’s object/types into the server, these get packaged at build of the game.

I’ve decided how to implement these in the back-end, and from a server perspective I have object serialization down, writing over TCP/UDP, as well as being able to call arbitrary messages on arbitrary server side objects.

On that last note is my question. I want to make this system somewhat platform dependent, so for unity I can’t serialize/send a gameobject. More importantly, I don’t think I should. I think a NetworkEntity/NetworkComponent shouldn’t have any strict dependencies on GameObject I think it should be a network-dependent way to represent a piece of an object in the gamespace. Some examples are a NetworkHealthController, or a NetworkPosition, both just represent some items that the server will manage updating/syncing the state of. Is this is a good design?

Some issues I forsee is, if you reference GameObject, like your network object does: GameObject.GetComponent<SomeType> We would fail. Do I just fail to build in this case? As I can’t really resolve things in the underlying C++ game-engine.

I hope I explained this well enough, and I appreciate any advice I can get.