Where am I? :)

[Kövesdán Gábor]

Giorgos Keramidas wrote:

>On 2006-03-04 00:44, K?vesd?n G?bor <gabor.kovesdan at t-hosting.hu> wrote:
>  
>
>>Hello,
>>
>>look at this:
>>
>>root at server# w
>>12:41AM  up 82 days, 10:05, 0 users, load averages: 0.00, 0.00, 0.00
>>USER             TTY      FROM              LOGIN@  IDLE WHAT
>>root at server#
>>
>>Where am I? :) I don't know exactly how it happened, but I'll
>>investigate, I have an idea and I'll report if I find out.
>>    
>>
>
>Some programs may tweak wtmp to `hide' users that are actively logged
>in.  One program that I know can do this is screen(1).  Hitting ``^A L''
>here, between successive `w' invocations, I can see this:
>
>root at flame:/root# w
> 2:04AM  up  2:10, 1 user, load averages: 0.07, 0.16, 0.19
>USER             TTY      FROM              LOGIN@  IDLE WHAT
>root at flame:/root# w
> 2:05AM  up  2:11, 2 users, load averages: 0.03, 0.14, 0.17
>USER             TTY      FROM              LOGIN@  IDLE WHAT
>root             pts/0    :0:S.0            2:05AM     - w
>root at flame:/root#
>
>  
>
And what do the other logged in users see? With my method I can 
completely hide, nobody can see me logged in. So I think it might be an 
opportunity to abusing. I'll send a PR soon, I just wanted to know 
before if somebody already knows about this trick.

Gabor Kovesdan

P.S.: It happened on a RELENG_5_3 system via SSH, but I suppose it can 
be triggered locally.