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SSHD Processes Using 100% CPU

Two Processes, both SSHD make up over 95% of my cpu utilization making my Leopard server run at 100% cpu utilization all the time. I kill them and they come back in 1/2 hour or so. Any ideas?

Xserver g5 x2, Mac OS X (10.5)

Posted on Dec 5, 2007 8:26 AM

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114 replies

Jan 26, 2008 12:22 AM in response to Worsham

I too have had the same problem. It's annoying because the only fix I had was to restart the computer all together. However, it does seem to be related to password issues as it only happens after a few random bots try to login to my computer. Or when I deliberately input incorrect passwords.

My temporary fix has been to add some IP based firewall rules to eliminate all the noise these annoying bots create. Basically I only allow SSH access on port 22 for IPs from home and work. Changing the SSHD port helps but the scanners still find the service now and then so the firewall is really the best method. We should all be doing that anyway in the first place.

Haven't had a problem since then. But hopefully Apple will get this fixed ASAP

Feb 1, 2008 5:48 PM in response to Worsham

It looks like this is a race condition with devfs - I haven't figured out why it's looping rather than simply returning the failure (which the forkpty->openpty->grantpt->ioctl chain correctly propagates up) but I opened a bug report with the relevant traces:

rdar://5713758

I'd recommend everyone else do the same and perhaps mention that ID so it gets prioritized up inside the engineering group.

Feb 13, 2008 12:13 PM in response to Jon Bell

After looking around in the secure logs on my system the other day, I sure am interested about such a blocker 🙂 I've had quite some brute force attempts the latest weeks. However, when I tried to install sshdfilter, it complaint about some post flight script that could not be run, and the Installer said that the installation had failed. But the sshdfilter app was apparently installed as I can find it on my Mac. I even saw in the system log that it tried to start, but then it complained about that it couldn't read some sshd.fifo file. I checked that file out, and it seemed I didn't have permission to read it.

What should be noted is that I first tried the installation and application on OS 10.5.2, which might not be supported as yet? Glad if I could help, and I would be glad if you could help me 🙂

Feb 28, 2008 3:38 PM in response to AndyOfLinux

Yeap - unfortunately the bug isn't due to network scanning or anything manageable. It's fairly deep in the way sshd opens a session up for a legitimate user (which is why it also affects Terminal.app) and there doesn't appear to be any way to solve that.

The only thing you can do is to open a bug report at bugreporter.apple.com - it'll be closed as a duplicate of Jon Bell's bug report (rdar://5685756) but it seems that the number of times a bug is reported does influence how quickly it gets fixed.

Mar 11, 2008 8:19 PM in response to Jon Bell

Has anyone tried installing/compiling openssh as a fix to this issue? I don't have the luxury of experimentation as both my leopard servers are production machines. I have no idea what potential repercussions could result but if someone out there has a test environment, it might be worth a try. The openssh project claims to work with Mac OS X and is sure to work in FreeBSD environments since it is based on BSD.

SSHD Processes Using 100% CPU

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