Re: sshit runs out of semaphores

2008-12-02 Thread Greg Larkin
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DA Forsyth wrote:
 Hiya
 
 I recently started (trying) to use sshit to filter the many brute 
 force sshd attacks.
 
 However, it has never worked on my box.  FreeBSD 7.0 p1.
 
 This morning it would only give a message (without exiting)
Could not create semaphore set: No space left on device
 at /usr/local/sbin/sshit line 322
 Every time it gets stopped by CTRL-C it leaves the shared memory 
 behind, allocated.
 
 I am going to reboot later and double the number of semaphores (in 
 loader.conf).
 I am running hobbit which uses 8, leaving only 2 free.  This may 
 solve this issue, but I'd appreciate any ideas and experienced 
 advice.
 
 A side issue is that sshit will only filter rapid fire attacks, but I 
 am also seeing 'slow fire' attacks, where an IP is repeated every 2 
 or 3 hours, but there seem to be a network of attackers because the 
 name sequence is kept up across many incoming IP's.  Is there any 
 script for countering these attacks?
 If not I'll write one I think.
 
 
 --
DA Fo rsythNetwork Supervisor
 Principal Technical Officer -- Institute for Water Research
 http://www.ru.ac.za/institutes/iwr/

Hi DA,

I previously used sshit to defend against SSH brute-force attacks but
never saw the semaphore problem that you reported.

However, I recently switched to sshguard for other reasons, and it has
worked well for defending against both high-speed and slow-speed
attacks.  You can get more information here:

http://sshguard.sourceforge.net/
http://www.freshports.org/security/sshguard-ipfw/

Hope that helps,
Greg
- --
Greg Larkin

http://www.FreeBSD.org/   - The Power To Serve
http://www.sourcehosting.net/ - Ready. Set. Code.
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Re: sshit runs out of semaphores

2008-12-02 Thread Bill Moran
In response to DA Forsyth [EMAIL PROTECTED]:

 Hiya
 
 I recently started (trying) to use sshit to filter the many brute 
 force sshd attacks.
 
 However, it has never worked on my box.  FreeBSD 7.0 p1.
 
 This morning it would only give a message (without exiting)
Could not create semaphore set: No space left on device
 at /usr/local/sbin/sshit line 322
 Every time it gets stopped by CTRL-C it leaves the shared memory 
 behind, allocated.

Have a look at ipcs and ipcrm, which will save you the reboots.

 A side issue is that sshit will only filter rapid fire attacks, but I 
 am also seeing 'slow fire' attacks, where an IP is repeated every 2 
 or 3 hours, but there seem to be a network of attackers because the 
 name sequence is kept up across many incoming IP's.  Is there any 
 script for countering these attacks?
 If not I'll write one I think.

My approach:
http://www.potentialtech.com/cms/node/16

-- 
Bill Moran
http://www.potentialtech.com
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Re: sshit runs out of semaphores

2008-12-02 Thread Beech Rintoul
On Tuesday 02 December 2008 04:54:27 Bill Moran wrote:
 In response to DA Forsyth [EMAIL PROTECTED]:
  Hiya
 
  I recently started (trying) to use sshit to filter the many brute
  force sshd attacks.
 
  However, it has never worked on my box.  FreeBSD 7.0 p1.
 
  This morning it would only give a message (without exiting)
 Could not create semaphore set: No space left on device
  at /usr/local/sbin/sshit line 322
  Every time it gets stopped by CTRL-C it leaves the shared memory
  behind, allocated.

 Have a look at ipcs and ipcrm, which will save you the reboots.

  A side issue is that sshit will only filter rapid fire attacks, but I
  am also seeing 'slow fire' attacks, where an IP is repeated every 2
  or 3 hours, but there seem to be a network of attackers because the
  name sequence is kept up across many incoming IP's.  Is there any
  script for countering these attacks?
  If not I'll write one I think.

 My approach:
 http://www.potentialtech.com/cms/node/16

I use denyhosts which adds the IP to a file called hosts_deny.ssh. It will 
keep the IP for however many days you set it for so a repeat even hours later 
will just get bounced.
-- 
---
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