Auditd misses accept syscalls from sshd

[Hassan Sultan]

On Fri, 02 Dec 2016 13:42:02 -0800, Nathan Cooprider  
<ncooprider at yankeehacker.com> wrote:
>
>
> Thanks for the suggestion. I'm getting other audit events from sshd  
> without restarting ssh. It's just the accept syscalls that do not show  
> up until after I >restart ssh:
>
> type=SYSCALL msg=audit(1480714641.465:54): arch=c000003e syscall=43  
> success=yes exit=5 a0=3 a1=7ffce3b031b0 a2=7ffce3b0319c a3=0 items=0  
> >ppid=1 pid=2602 auid=4294967295 uid=0 gid=0 euid=0 suid=0 fsuid=0  
> egid=0 sgid=0 fsgid=0 tty=(none) ses=4294967295 comm="sshd"  
> exe="/usr/sbin/>sshd" key=(null)
>
> I think that indicates the kernel is sending up audit messages. My  
> question is why the above message fails to come up until after I've  
> restarted ssh.
>

(I was the person having that issue almost 2 years ago)

I never fully investigated it, but came up with one theory explaining it :

- accept is a blocking syscall , it might be that sshd started and the  
syscall was initiated before the audit rule was loaded. This would explain  
why you see the event when restarting sshd.

Don't use the tcp connection time to evaluate whether the auditing worked  
properly, but rather when the initial accept call was made, which  
basically amounts to when sshd is started.


Hassan
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