It's hard to give specific advice from what you've posted here but I do have some generic advice based on a post I wrote ages ago back when I could still be bothered to blog.
Don't Panic
First things first, there are no "quick fixes" other than restoring your system from a backup taken prior to the intrusion, and this has at least two problems.
- It's difficult to pinpoint when the intrusion happened.
- It doesn't help you close the "hole" that allowed them to break in last time, nor deal with the consequences of any "data theft" that may also have taken place.
This question keeps being asked repeatedly by the victims of hackers breaking into their web server. The answers very rarely change, but people keep asking the question. I'm not sure why. Perhaps people just don't like the answers they've seen when searching for help, or they can't find someone they trust to give them advice. Or perhaps people read an answer to this question and focus too much on the 5% of why their case is special and different from the answers they can find online and miss the 95% of the question and answer where their case is near enough the same as the one they read online.
That brings me to the first important nugget of information. I really do appreciate that you are a special unique snowflake. I appreciate that your website is too, as it's a reflection of you and your business or at the very least, your hard work on behalf of an employer. But to someone on the outside looking in, whether a computer security person looking at the problem to try and help you or even the attacker himself, it is very likely that your problem will be at least 95% identical to every other case they've ever looked at.
Don't take the attack personally, and don't take the recommendations that follow here or that you get from other people personally. If you are reading this after just becoming the victim of a website hack then I really am sorry, and I really hope you can find something helpful here, but this is not the time to let your ego get in the way of what you need to do.
You have just found out that your server(s) got hacked. Now what?
Do not panic. Absolutely do not act in haste, and absolutely do not try and pretend things never happened and not act at all.
First: understand that the disaster has already happened. This is not the time for denial; it is the time to accept what has happened, to be realistic about it, and to take steps to manage the consequences of the impact.
Some of these steps are going to hurt, and (unless your website holds a copy of my details) I really don't care if you ignore all or some of these steps, that's up to you. But following them properly will make things better in the end. The medicine might taste awful but sometimes you have to overlook that if you really want the cure to work.
Stop the problem from becoming worse than it already is:
- The first thing you should do is disconnect the affected systems from the Internet. Whatever other problems you have, leaving the system connected to the web will only allow the attack to continue. I mean this quite literally; get someone to physically visit the server and unplug network cables if that is what it takes, but disconnect the victim from its muggers before you try to do anything else.
- Change all your passwords for all accounts on all computers that are on the same network as the compromised systems. No really. All accounts. All computers. Yes, you're right, this might be overkill; on the other hand, it might not. You don't know either way, do you?
- Check your other systems. Pay special attention to other Internet facing services, and to those that hold financial or other commercially sensitive data.
- If the system holds anyone's personal data, immediately inform the person responsible for data protection (if that's not you) and URGE a full disclosure. I know this one is tough. I know this one is going to hurt. I know that many businesses want to sweep this kind of problem under the carpet but the business is going to have to deal with it - and needs to do so with an eye on any and all relevant privacy laws.
However annoyed your customers might be to have you tell them about a problem, they'll be far more annoyed if you don't tell them, and they only find out for themselves after someone charges $8,000 worth of goods using the credit card details they stole from your site.
Remember what I said previously? The bad thing has already happened. The only question now is how well you deal with it.
Understand the problem fully:
- Do NOT put the affected systems back online until this stage is fully complete, unless you want to be the person whose post was the tipping point for me actually deciding to write this article. I'm not going to link to that post so that people can get a cheap laugh, but the real tragedy is when people fail to learn from their mistakes.
- Examine the 'attacked' systems to understand how the attacks succeeded in compromising your security. Make every effort to find out where the attacks "came from", so that you understand what problems you have and need to address to make your system safe in the future.
- Examine the 'attacked' systems again, this time to understand where the attacks went, so that you understand what systems were compromised in the attack. Ensure you follow up any pointers that suggest compromised systems could become a springboard to attack your systems further.
- Ensure the "gateways" used in any and all attacks are fully understood, so that you may begin to close them properly. (e.g. if your systems were compromised by a SQL injection attack, then not only do you need to close the particular flawed line of code that they broke in by, you would want to audit all of your code to see if the same type of mistake was made elsewhere).
- Understand that attacks might succeed because of more than one flaw. Often, attacks succeed not through finding one major bug in a system but by stringing together several issues (sometimes minor and trivial by themselves) to compromise a system. For example, using SQL injection attacks to send commands to a database server, discovering the website/application you're attacking is running in the context of an administrative user and using the rights of that account as a stepping-stone to compromise other parts of a system. Or as hackers like to call it: "another day in the office taking advantage of common mistakes people make".
Why not just "repair" the exploit or rootkit you've detected and put the system back online?
In situations like this the problem is that you don't have control of that system any more. It's not your computer any more.
The only way to be certain that you've got control of the system is to rebuild the system. While there's a lot of value in finding and fixing the exploit used to break into the system, you can't be sure about what else has been done to the system once the intruders gained control (indeed, its not unheard of for hackers that recruit systems into a botnet to patch the exploits they used themselves, to safeguard "their" new computer from other hackers, as well as installing their rootkit).
Make a plan for recovery and to bring your website back online and stick to it:
Nobody wants to be offline for longer than they have to be. That's a given. If this website is a revenue generating mechanism then the pressure to bring it back online quickly will be intense. Even if the only thing at stake is your / your company's reputation, this is still going generate a lot of pressure to put things back up quickly.
However, don't give in to the temptation to go back online too quickly. Instead move with as fast as possible to understand what caused the problem and to solve it before you go back online or else you will almost certainly fall victim to an intrusion once again, and remember, "to get hacked once can be classed as misfortune; to get hacked again straight afterward looks like carelessness" (with apologies to Oscar Wilde).
- I'm assuming you've understood all the issues that led to the successful intrusion in the first place before you even start this section. I don't want to overstate the case but if you haven't done that first then you really do need to. Sorry.
- Never pay blackmail / protection money. This is the sign of an easy mark and you don't want that phrase ever used to describe you.
- Don't be tempted to put the same server(s) back online without a full rebuild. It should be far quicker to build a new box or "nuke the server from orbit and do a clean install" on the old hardware than it would be to audit every single corner of the old system to make sure it is clean before putting it back online again. If you disagree with that then you probably don't know what it really means to ensure a system is fully cleaned, or your website deployment procedures are an unholy mess. You presumably have backups and test deployments of your site that you can just use to build the live site, and if you don't then being hacked is not your biggest problem.
- Be very careful about re-using data that was "live" on the system at the time of the hack. I won't say "never ever do it" because you'll just ignore me, but frankly I think you do need to consider the consequences of keeping data around when you know you cannot guarantee its integrity. Ideally, you should restore this from a backup made prior to the intrusion. If you cannot or will not do that, you should be very careful with that data because it's tainted. You should especially be aware of the consequences to others if this data belongs to customers or site visitors rather than directly to you.
- Monitor the system(s) carefully. You should resolve to do this as an ongoing process in the future (more below) but you take extra pains to be vigilant during the period immediately following your site coming back online. The intruders will almost certainly be back, and if you can spot them trying to break in again you will certainly be able to see quickly if you really have closed all the holes they used before plus any they made for themselves, and you might gather useful information you can pass on to your local law enforcement.
Reducing the risk in the future.
The first thing you need to understand is that security is a process that you have to apply throughout the entire life-cycle of designing, deploying and maintaining an Internet-facing system, not something you can slap a few layers over your code afterwards like cheap paint. To be properly secure, a service and an application need to be designed from the start with this in mind as one of the major goals of the project. I realise that's boring and you've heard it all before and that I "just don't realise the pressure man" of getting your beta web2.0 (beta) service into beta status on the web, but the fact is that this keeps getting repeated because it was true the first time it was said and it hasn't yet become a lie.
You can't eliminate risk. You shouldn't even try to do that. What you should do however is to understand which security risks are important to you, and understand how to manage and reduce both the impact of the risk and the probability that the risk will occur.
What steps can you take to reduce the probability of an attack being successful?
For example:
- Was the flaw that allowed people to break into your site a known bug in vendor code, for which a patch was available? If so, do you need to re-think your approach to how you patch applications on your Internet-facing servers?
- Was the flaw that allowed people to break into your site an unknown bug in vendor code, for which a patch was not available? I most certainly do not advocate changing suppliers whenever something like this bites you because they all have their problems and you'll run out of platforms in a year at the most if you take this approach. However, if a system constantly lets you down then you should either migrate to something more robust or at the very least, re-architect your system so that vulnerable components stay wrapped up in cotton wool and as far away as possible from hostile eyes.
- Was the flaw a bug in code developed by you (or a contractor working for you)? If so, do you need to re-think your approach to how you approve code for deployment to your live site? Could the bug have been caught with an improved test system, or with changes to your coding "standard" (for example, while technology is not a panacea, you can reduce the probability of a successful SQL injection attack by using well-documented coding techniques).
- Was the flaw due to a problem with how the server or application software was deployed? If so, are you using automated procedures to build and deploy servers where possible? These are a great help in maintaining a consistent "baseline" state on all your servers, minimising the amount of custom work that has to be done on each one and hence hopefully minimising the opportunity for a mistake to be made. Same goes with code deployment - if you require something "special" to be done to deploy the latest version of your web app then try hard to automate it and ensure it always is done in a consistent manner.
- Could the intrusion have been caught earlier with better monitoring of your systems? Of course, 24-hour monitoring or an "on call" system for your staff might not be cost effective, but there are companies out there who can monitor your web facing services for you and alert you in the event of a problem. You might decide you can't afford this or don't need it and that's just fine... just take it into consideration.
- Use tools such as tripwire and nessus where appropriate - but don't just use them blindly because I said so. Take the time to learn how to use a few good security tools that are appropriate to your environment, keep these tools updated and use them on a regular basis.
- Consider hiring security experts to 'audit' your website security on a regular basis. Again, you might decide you can't afford this or don't need it and that's just fine... just take it into consideration.
What steps can you take to reduce the consequences of a successful attack?
If you decide that the "risk" of the lower floor of your home flooding is high, but not high enough to warrant moving, you should at least move the irreplaceable family heirlooms upstairs. Right?
- Can you reduce the amount of services directly exposed to the Internet? Can you maintain some kind of gap between your internal services and your Internet-facing services? This ensures that even if your external systems are compromised the chances of using this as a springboard to attack your internal systems are limited.
- Are you storing information you don't need to store? Are you storing such information "online" when it could be archived somewhere else. There are two points to this part; the obvious one is that people cannot steal information from you that you don't have, and the second point is that the less you store, the less you need to maintain and code for, and so there are fewer chances for bugs to slip into your code or systems design.
- Are you using "least access" principles for your web app? If users only need to read from a database, then make sure the account the web app uses to service this only has read access, don't allow it write access and certainly not system-level access.
- If you're not very experienced at something and it is not central to your business, consider outsourcing it. In other words, if you run a small website talking about writing desktop application code and decide to start selling small desktop applications from the site then consider "outsourcing" your credit card order system to someone like Paypal.
- If at all possible, make practicing recovery from compromised systems part of your Disaster Recovery plan. This is arguably just another "disaster scenario" that you could encounter, simply one with its own set of problems and issues that are distinct from the usual 'server room caught fire'/'was invaded by giant server eating furbies' kind of thing.
... And finally
I've probably left out no end of stuff that others consider important, but the steps above should at least help you start sorting things out if you are unlucky enough to fall victim to hackers.
Above all: Don't panic. Think before you act. Act firmly once you've made a decision, and leave a comment below if you have something to add to my list of steps.
Please don't take offense to this but I strongly suggest you bring in a local area IT consulting firm that specializes in systems and network administration. I also came from a programming background many moons ago and learned many hard lessons on the do's and don'ts of managing a networked server environment. I (thankfully) had alot of mentors and help over the years, because without it, who knows what kind of smoldering wreckage would be left behind.
Moving right along now to your original question: I see two mistakes, one being Linux: don't get me wrong, I love Linux and use it in all kinds of various roles, but as a sole server in a small company that (again, no offense) doesn't have a full-time sysadmin is asking for trouble. Finding competent Linux administrators (and it's even harder to find ones that follow best practices) is not easy. Down the road, if you leave or you hire a new person to take over your duties, who's going to look after it?
Assuming you're under 75 end-users, I would strongly recommend Microsoft Small Business Server 2011 Standard on solid tier-1 hardware (like Dell, HP, IBM) with a 3-year on-site/4-hour replacement warranty. Have at least a RAID 1 mirrored array for the data (and another for the system if you can afford it). Get at least 8GB of RAM, 12GB is better. Invest in an offline/off-site backup: you can start with a couple of external drives or a tape drive, but something you can take off-site with you every night.
I'm also not sold on your suggestion for a custom "all-in-one" database: there are so many better, more viable software options out there, that unless you have some very specific niche requirements that only a custom solution can provide, you'd be much better off using a well-supported 3rd-party offering. You have to resist the "I can write something" programmer urges and think about supporting this solution long-term.
And finally, I think you and your employer need to decide what you role is going to be at this company. It sounds like you're new there and while you're right, they likely do need to upgrade their systems, you don't want to bite off more than you can chew and fail to provide whatever it was that you were hired there to do.
EDIT
There's a lot of opinions floating around right now, so I'm going to take a step back and hopefully provide some platform-agnostic advice that will be of use to you regardless of what you end up going with:
Do a complete inventory of all systems and devices; check warranty status of hardware (if it's a Dell, IBM, etc. you should be able use the service tag to get a warranty check; if it's a white box server, they may still have some sort of identifier, but you'll have to call to find out what the status is most likely).
Do a complete inventory of data: Don't trust that they have no data on their C: drives; they probably do, actually they probably have PST files all over the place of old mail. Find out what's critical, what's being backed up, what's not being backed up, how it's being backed up and whether anything is taken off-site or not. FIX THIS FIRST. RIGHT NOW. If they have no backup setup, go buy an external USB drive at a Big Box store for now and use NTBackup (it's likely on that server already) and do a full backup and take it off-site with you. If they have backup in place, go do a test restore (see below).
Check patch levels on all systems (get #2 sorted out first!): not just Windows Updates, but Java and all Adobe products especially and update accordingly (might want to do #4 first so you know what machines are higher-priority than others. i.e. that workstation for the part-time staff member could stand a botched update much more than the accountant who cuts the pay checks).
Talk to your users: find out what's working well, what's not working, get a feel for everyone's level of change tolerance, their comfort level with IT (you may be recruiting a helper to get things in order), and any wish lists they may have. Understand their business processes; as a sysadmin, your priority should be ensuring that the systems the business depends on to function are working in good order and to do that, you need to know how everyone uses those systems.
After #1, you should have an idea of how the network's setup. Look for any old hubs that can be replaced; you'll want at least 10/100 everywhere, switch-wise. Check the firewall/router (make sure there is one), check for any open wi-fi access points, etc.
If you do go the Linux route, stick with a distro that's well-supported by the community (Ubuntu would be a good choice) and set it up on whatever hardware you can afford (as you know, a LAMP box could be an off-lease P4 workstation for now) and as isolated from the currently-working system as possible. As a learning exercise (and could pay huge dividends in a disaster recovery scenario), try to get the core applications that are running on the current server working on another Windows box first -- use your full backup you did in #2 to do a test restore; have fun with that :)
As for your test setup, you can opt to buy something beefy with lots of RAM and then you can virtualize (ESXi is free, so is XenServer, so is VirtualBox) but if the current server is Windows 2003 or older, you can likely get that FoxPro application working on an off-lease Windows XP workstation for cheap.
Now pat yourself on the back; you now have good backups; you also did a test restore and now have a better understanding of how everything works together. You also likely have a (long) priority TODO list that'll keep you busy for the foreseeable future.
Oh and when that's all done, you now have a test environment you can start building your Utopian "dream" system... or maybe take a vacation :)
Best Answer
This is a situation I've run into often, and I pretty much always do the same thing: IPSec.
Whether it works for you is dependent on whether there's an IPv4 overlap between their network and yours, which you don't say. But I know you have clue, and if there was this additional hurdle I think you'd've mentioned it, so let's assume for now that there isn't any overlap.
Set up an IPSec tunnel between their core router and yours, using PSK authentication. Most good routers will speak it, and it's not hard to do. Once you have a tunnel in place, you can trust the identity of any packets that come down it (note: I'm not saying you can trust the content of the packets, only that you can be sure they really do come from Potentially-Hostile Partner).
So then you can apply access filters to traffic coming out the tunnel, and precisely restrict what hosts on your network they have the capability to access, and on what ports, and from which machine(s) at their end (though that latter restriction is less useful as you have no control over whether devices on their network are maliciously changing ther IP addresses to elevate their access rights to your end).
Linking the networks, rather than having any random trusted client at their end use an individual VPN client, works better in my experience, not least because you'll either end up with a full-time job managing client access tokens - issuing new ones, revoking old ones, grumbling about people copying them or dealing with the fallout of mandating that any token can only be used once - or you'll issue one token that everyone will use, and you'll have lost any control over who's using it and where they're using it from. It also means that the complexity is in the core, where it's best managed.
I've had some such tunnels, between my networks and those of the PHPs, running for a decade, and they just Do Their Thing. From time to time someone needs a new machine on their end able to access some new dev box or other resource on our end, and it's a simple change to an interface access list, a one-line fix to my own kit that I can do in seconds, and everything is working. No client installs. No endpoint complications at all.
I find the v6 idea fascinating, but I suspect that it'll run onto the rocks when some v4-only client, or something riddled with v6 bugs because it's so untested, comes along and really-really-really-pretty-please needs access to your network resources.