No forkbomb protection by default !?!

befortin · Apprentice Joined: 10 Feb 2004 Posts: 193

Here's the reason why a user shouldn't have to change the default limits to secure their system:

steveb · Advocate Joined: 18 Sep 2002 Posts: 4564

befortin · Apprentice Joined: 10 Feb 2004 Posts: 193

99% of Windows users want a secure system, even if they don't know how to secure their systems. You don't need to be CISSP, Security+, Checkpoint, etc. certified to ask for a secure system. You also don't need to run 100 shell servers to ask for a sane default setting. You also don't need to run gcc hardened, hardened kernel, SELinux and GRSecurity to ask for a sane default setting.

Have you read the Jason Miller article? It's about someone who runs awstats on a server. A hacker get shell access because of a awstats security. The sysadmin then talks to the hacker :

steveb · Advocate Joined: 18 Sep 2002 Posts: 4564

befortin · Apprentice Joined: 10 Feb 2004 Posts: 193

I think almost the same thing that you do. Limits is, like, the 1000th priority. There are tons of things that need to be configured and tweaked to get a secure system, ant limits is really not important.

nat has posted some solutions on Bugzilla, thought I'm not knowledgeable enough to say if it would or wouldn't work...

It's true that an awstats server should be secured and no one should be able to gain a shell access on it. But, IMHO, it's also true that if they do get shell access, that shell should be somewhat secured.

I think that what Jason Miller says regarding this issue is, again, interesting :

steveb · Advocate Joined: 18 Sep 2002 Posts: 4564

This Jason Miller guy is right.

I just see the problem with Gentoo is, that most of the Gentoo packages do NOT modify the stuff which is installed by portage. Gentoo does not heavy patch the whole system. I like that very much. If the limits would now be modified by portage or the install process, then some developer at Gentoo needs to take the responsability for that task. This brings them more trouble then benefit (since the one needing to modify the limit will anyway know how to do so). I personaly think that a link (as it is now) in the installation guide, pointing to some security issues is the easy way of handling such a huge topic, without investing to much time.

What do you think?

cheers

SteveB

befortin · Apprentice Joined: 10 Feb 2004 Posts: 193

I agree with you. I also like that Gentoo leaves the "default" config of the packages.

I think that the devs prefer not to fix this "problem" because it really is a pain in the ass to fix it, and that because most other distros doesn't put "sane" default limits, then Gentoo can do the same without being regarded as an "insecure" distro.

Let's for the Linus to put this limits thing in the kernel and in the meantime, everyone who wants to secure their Gentoo box will be able to do so by reading the docs. Anyway, Gentoo is not often used in production environments...

lkarayan · n00b Joined: 28 Mar 2005 Posts: 14

steveb · Advocate Joined: 18 Sep 2002 Posts: 4564

ydleiF · Posted: Fri Apr 01, 2005 4:59 pm Post subject: Grsecurity, and minor rant

You want a pretty good solution to this and other (TONS of others) problems? Look at the grsecurity patch. I don't know if it's in portage or anything, but if it's not big deal, learn how to build your own kernels, and patch etc. If you're going to run servers, you'd be expected to know how, anyway.

No it's not the end all, but it's a great start. It stops fork bombs of any type I tried dead in it's tracks, and also logs what's going on so you can abuse somebody later. Since it's at the kernel level (as opposed to ulimits, at the application level), the limits are applied to everything. Including services started at boot.

And now I just wanted to cast my opinions. It's gonna sound elitist, so if you don't like it, too bad.

1) If you don't understand things like this thread is about (which honestly is just the tip of the iceberg), don't run a shell server. In fact, please don't run a server period. We don't need any more cracked (note: "hacked" is NOT the right term) systems being used to perform D/DDoS attacks, send spam, etc.

2) While I don't think you should run a server without this knowledge and understanding, at the same time the best education is by experience. You want to learn? Consider setting up an isolated system, and let the kiddies have at it. Give untrusted folks shells. You'll be learning so fast, you won't be able to keep up.

3) I've always viewed Gentoo as providing a foundation, which you then build upon. YOU CAN'T MAKE EVERYBODY HAPPY with a foundation. Some will like it, others will not. Guess what folks, this is what Gentoo is about. Build it the way you want it.

ydleiF · Posted: Fri Apr 01, 2005 5:05 pm Post subject:

Mad_Jester · Tux's lil' helper Joined: 08 Jan 2004 Posts: 85

There are some insinuations being made that people who are asking for default limits are lazy, incompetent, or both, and shouldn't even be running a server. Well, sometimes that is true. It is true and we have to live with that. Sometimes the company doesn't hire an experienced admin, or they hire an admin with MS experience only. Occasionally they are a little firm who doesn't think that security matters, and that they won't be targeted. They don't understand the risks. Does that stop their server from being compromised and flooding mine with spam? Or from being a point from which they can target other sytems? Of course not.

Experienced administrators are generally busy, and overworked. Sometimes they even forget things. Ever forget? It's happened to me. That doesn't mean they are incompetent, lazy, or that they shouldn't run a server. We need to be more realistic about what people are experiencing out there. Real gentoo users are complaining about something. People are posting articles that show Gentoo in a poor light. Let's not just ignore it because it doesn't fit in with our ideal expectations of how linux and Gentoo should be used. For better or worse linux has garnered a reputation as a "secure" system. This may be bad because people have an expectation that their system is going to be secure. If by default we leave a few small holes, and they come to light, well it damages Gentoo's reputation. It makes Gentoo less appealing as a server platform. Gentoo still isn't taken seriously as a server platform by most linux and unix engineers. It only takes a few events like this to really start to cement that idea in peoples minds, "Gentoo isn't secure, I better use Debian."

Personally security was one of the reasons I chose to start using Gentoo as my primary server platform. I do a lot of the things Steve B. mentioned, (hardened kernel, GRSecurity, tightened permissions, strict firewall, encryption, etc.) as well as a few more. I don't let people have shell accounts, and I do a good job of keeping things tight. But I didn't remember the limits file. Probably because it has been years since I have used a system that didn't have some defaults in place. My unix systems had limits, Debian has limits, why not Gentoo? Now the chances of someone getting access and causing me some forkbomb problems are smaller than me winning the lottery (and I don't buy tickets), but I still think some sane defaults should have been there. Both for those who forget, and those who don't know any better (even if you think they should). Because while this wouldn't allow someone to use a compromised system to blast out spam, or launch attacks against your systems, we need to stop thinking in terms of, "Someone elses problem".

Sane limits won't hurt anyone. They may be a temporary inconvenience, but they won't cause any serious problems (you run into them, you change them). Not having them could. Not just to someone who with or without tight security gets "hacked", but to Gentoo's reputation as a secure platform. I see this as an oversight. Something that should have been in place all along. To be dogmatic about configuration changes, is to ignore the world we live in.

nat · Apprentice Joined: 04 Sep 2002 Posts: 205

Looks like they won't lower the default limits in the kernel. :-(

I think its a shame that you have to explain to people why the principle of least privilege is a good thing.

Anyway... try this:

feld · Guru Joined: 29 Aug 2004 Posts: 593 Location: WI, USA

LOOKY HERE. I just saw this. I thought you guys might enjoy seeing it too.

nat · Apprentice Joined: 04 Sep 2002 Posts: 205

DrSpirograph · n00b Joined: 05 Apr 2003 Posts: 69

nat · Apprentice Joined: 04 Sep 2002 Posts: 205

Sakkath · Posted: Wed Jul 26, 2006 8:49 pm Post subject:

Why would you let a user you don't trust on the server? Watch who you are allowing access to.

I want to be able to crash my system, I do not like restrictions. If a user misbehaves, punish them :>. If you don't want it to happen, please use the Gentoo Hardened Project Guide.

If you don't want to read, Gentoo isn't for you, or, Linux for that matter. Gentoo's point is to let the user do what they want, if you don't want to have a bare-bones system, use Ubuntu, or something, lol.
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