Remote Root Exploit In lsh

skookum writes "After last week's OpenSSH patch-fest, a lot of people suggested GNU lsh as a replacement. Unfortunately, it seems that the lsh team has recently discovered a heap overflow bug of their own that can lead to compromise. An exploit was posted to BugTraq two days ago. Happy patching."

Comments

Ha-Ha

[Anonymous Coward]

I find it entertaining that the GNU zealot hippies suggest lsh as a replacement. That's like suggesting that the HURD is a replacement for the Linux kernel. Always trying to one-up the *BSD people by making something "more free", but never living up to the hype.

BTW, *who* uses lsh????

Can someone explain to me why..

[Anonymous Coward]

We have a GNU ordained version of the SSH protocols when OpenSSH is doing a fantastic job?

Even if you are going to argue the BSD vs. GPL license issue, the lsh devs could have just taken the OpenSSH code, made some slight changes, and re-released it under the GPL.

So again I ask: Why?

Telnet

[Henry V .009]

I was going to repeat "switch to Telnet joke" that I made last time, but I just can't get up will this time. These bugs are killing us. I seriously think that we need to take some time to consider how Open Source projects do security. The "more eyes" mantra doesn't cut it. We need security models, standards, testing, and god knows what else. We need to look at which projects have been successful, and which have been miserable security failures. I know the open source community can do a lot better.

Re:Telnet

[ajs]

These bugs are not killing us. In fact, they're helping us to make our code stronger.

I'm so sick of the "there are bugs in it, let's switch" mentallity. There are bugs in every piece of software ever written. Why? Because human beings have a hard time specifying exactly what they want.

Sometimes those bugs are dangerous (as in buffer overflows), but if you look at your average piece of source code long enough -- source of ANY number of lines -- I bet you can find a bug in it.

So, we should all switch to the abacus? No, we should all make sure we spend time and money on the problem of finding bugs before the black-hats do. And that's why I buy software like Red Hat... because they actually spend some of that money on auditing for security, and I like the results (many bugs found and killed).

Re:Telnet

[TomV]

Why the hell not? Good bridges are the ones that don't fall down

That's not the same as saying that good bridges have no faults. Bridges are built with a large safety factor. A large amount of the steel wire in the Brooklyn Bridge cables is hideously substandard, slipped in there by a currupt subcontractor. But because the safety factors were in place, even though the cables are probably about 5/6 as strong as they were designed to be, because they were designed to be 4 times as strong as strictly necessary, the Brooklyn Bridge is still there today. They paid for a lot more steel than strictly necessary, but they were proved right to have done so.

The bridge is Verifiably Strong Enough, but it certainly isn't Fault-Free. It was a product of defensive engineering, and software containing the inevitable bugs can be made much safer by taking a defensive approach to programming. It's better not to have an out-of-bounds situation at all, but that's no reason not to do bounds-checking wherever an OOB might pose a hazard. Yes it costs money to code all those extra checks, but that's what engineers do in most other disciplines.

TomV

Still diversity is good.

[Coryoth]

Okay, there's a hole here, that's definitely bad. Still it would be nice if lsh could manage to gain some share of the ssh market. It has worried me for a while that OpenSSH has become the standard, which, unfortunately, creates a monoculture. A monoculture of ssh implementations is as vulnerable to massive infection as a monculture of windows boxes (okay, maybe windows has more holes, but its the massive part I'm concerned with).

If the market on ssh implementations was a little more split, it would be a little more difficult to write a worm that could wreak utter havoc. Repeat after me: Monoculture is bad.

Jedidiah.

Re:The standard conclusion

[GammaTau]

Nothing is 100% secure, nothing is flawless, all operating systems are imperfect pieces of junk [...]

Which is why software monoculture is bad. The existence of competing implementations is always a good thing whether it's OpenSSH vs. GNU lsh or something else. That way not everything is compromised in one swoop once a new security flaw is discovered.

After 20+ years of buffer overflow exploits...

[kcbrown]

...you'd think that developers would finally know how to write software that doesn't have such vulnerabilities.

But unfortunately we don't seem to have made that much progress, despite the reasonably large number of development tools we have that address such issues (including anything from memory debuggers to string libraries). I mean, really ... people are still writing these things in C ... in the 21st century! I'm a big fan of picking the right tool for the job, but I think it should be clear by now that C isn't the right tool for writing secure software. There are simply too many ways to screw up.

I think it's time we started writing system software (that is, software which provides services but which runs as a process under the OS) in a language which doesn't have these problems. And if a suitable language is unavailable, that argues strongly for creating that language.

You might still have to worry about buffer overflow exploits against the kernel, but that's a much more manageable problem.

Re:After 20+ years of buffer overflow exploits...

[vt0asta]

First things, first. C was meant to be a highly portable version of assembly. C successfully facilatated porting operating systems AND applications that used those operating systems.

People often think of C the wrong way, and that is often because languages considered "safe" borrow heavily from C syntax. If you have ever programmed in assembly/machine language, you know the programming bugs can do quite nasty and unexplained things (sometimes much worse than a buffer overflow). However, having coded in assembly one often becomes more rigorous with their coding, that same rigor is what is needed to carry over to C, and is what is lacking with some of the C coders of today.

Second, system software also often needs a low memory footprint. System developers often want to know where every little bit of memory went, and often find compiled code barely tolerable. Not everyone can afford the luxury of loading a perl, python, java, byte code interpretor du jour just to send and read data, manipulate strings, and do stuff with files.

System software is very different from operating systems, and calls for a different language.

Maybe you're right, problem is, many have tried almost all have failed to gain popularity for systems coding. Big problem for your argument and for developers who know, almost all of those different languages were first written in...drum roll...."C".

hubris is never safe

[Build6]

I remember reading the alert for the OpenSSH bug, where one of the options listed was to upgrade to lsh - not "change to", "try using", or anything of the sort, but "upgrade" - and I thought then that that demonstrated an unnecessarily... high-horse-y attitude. I'll bet they regret saying that now... . Humility really IS the best policy.

Re:I have to laugh

[cduffy]

looks don't mean jack or shit.

In code, looks mean quite a lot.

Cleaner, more readable code is easier to audit.
Cleaner, more readable code is easier to bugfix.
Cleaner, more readable code is easier to add features to.
Cleaner, more readable code is simply Good Stuff.

Smug.

[Alioth]

Serves those smug bastards right who were gloating the other day about how they use lsh and how it is so much better than OpenSSH. Hoist by their own petard, so it seems.

I _never_ gloat about running different software to $COMPROMISED_SW of the day. Just because I run exim, I don't think I'm magically more secure than a sendmail user. Exim users must keep up with the patches as well. Same goes for qmail. If you sit there smugly saying how superior your piece of software is, you're going to get bitten in the ass sooner or later, or at least end up looking very silly after all the gloating to find you're vulnerable too.

Dudes, doesn't matter what you run: don't gloat about it - be paranoid about the security of what you run, and keep up with the patches.

lsh Pre-dates OpenSSH

[divec]

Does it exist solely because of the non-GNUness of other implementations?

When lsh was started, OpenSSH didn't exist. The original SSH was free till version 1.2.12, but was then put under a more restrictive licence. The licence on ssh version 2 was more restrictive still (I think it wasn't even free-as-in-beer). lsh was intended to be a Free, Open-Source replacement to ssh.

Then the OpenBSD people took the old, free 1.2.12 version of ssh, fixed all the known bugs which had accumulated since that release and updated it with the new features in the SSH protocol. This is OpenSSH.

Maybe the standard Winlot conclusion

[RoLi]

nothing is flawless

Nobody ever claimed it would be.

However I've personally experienced that many systems are more secure than others. Almost all security problems on Unix didn't affect me (like this, BTW. This is actually the first time I've ever heard about lsh) and often were hyped up. In the meantime I get tens of Windows-Virus-mails and attemted IIS infections per day.

The true conclusion:

Windows is like a 50 year old car without safety belts, Unix is like a modern Volvo with safety belts and airbags.

Neither car is "flawless" and you can die in the Volvo too.