Re: [CentOS] VSFTPD accepting same user/session from different IP addresses

2010-03-22 Thread Kai Schaetzl
Dirk H. Schulz wrote on Mon, 22 Mar 2010 15:41:55 +0100:

> makes me think that the same session with the same commands is 
> "delivered" via 2 outgoing gateways, because it would be very 
> complicated to have two ftp clients issue the same command in the same 
> second. Know what I mean?

No, I don't know. This is *one* client and I bet it's the dreaded 
Filezilla. It opens multiple parallel connections if you don't configure 
it correctly. And then it's just a matter of how your internet connection 
and gateway is setup. This is a big institution with a big IP range 
(whois.ripe.net). It's not your usual type of connection, but it's nothing 
wrong with it.

> 
> By the way, vsftpd seems not to handle this situation securely, so I 
> want to prevent any occurance of it.

Again, what's the security problem here?


Kai

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Re: [CentOS] VSFTPD accepting same user/session from different IP addresses

2010-03-22 Thread Dirk H. Schulz
Hi Kai,

Am 22.03.10 15:31, schrieb Kai Schaetzl:
> Dirk H. Schulz wrote on Mon, 22 Mar 2010 13:41:50 +0100:
>
>
>> What I am concerned about is the fact that the client sends out using
>> various gateways at once. Is there some configuration item in VSFTPD
>> which can prevent this and reject packets from the additional ip addresses?
>>  
> Note, this is not the same session, it's a different connect with the same
> user credentials. I don't see a problem with this. It's not a security
> problem and it's hardly a load problem. Users usually don't have more than
> one IP at their disposal at the same time. This is one of the few cases where
> this is different.
>
Thanks for the fast answer - and sorry for insisting. This
> Wed Mar 10 15:52:33 2010 [pid 15232] [uploaduser] OK MKDIR: Client 
> "195.200.70.40", "/04 LV gelieferte Daten 04_2010/04 LV 
> Seiten/Jungz?chter"
> Wed Mar 10 15:52:33 2010 [pid 15231] [uploaduser] FAIL MKDIR: Client 
> "195.200.70.41", "/04 LV gelieferte Daten 04_2010/04 LV 
> Seiten/Jungz?chter"
makes me think that the same session with the same commands is 
"delivered" via 2 outgoing gateways, because it would be very 
complicated to have two ftp clients issue the same command in the same 
second. Know what I mean?

By the way, vsftpd seems not to handle this situation securely, so I 
want to prevent any occurance of it.

Dirk
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Re: [CentOS] VSFTPD accepting same user/session from different IP addresses

2010-03-22 Thread Kai Schaetzl
Dirk H. Schulz wrote on Mon, 22 Mar 2010 13:41:50 +0100:

> What I am concerned about is the fact that the client sends out using 
> various gateways at once. Is there some configuration item in VSFTPD 
> which can prevent this and reject packets from the additional ip addresses?

Note, this is not the same session, it's a different connect with the same 
user credentials. I don't see a problem with this. It's not a security 
problem and it's hardly a load problem. Users usually don't have more than 
one IP at their disposal at the same time. This is one of the few cases where 
this is different.

AFAIK, there is no option to allow only x logins per user, only x logins per 
IP. You could go to the vsftpd mailing list (if there is one) and ask about 
this additional feature.

Kai

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[CentOS] VSFTPD accepting same user/session from different IP addresses

2010-03-22 Thread Dirk H. Schulz

Hi folks,

I have found the following in my logs:

Wed Mar 10 15:52:33 2010 [pid 15232] [uploaduser] OK MKDIR: Client 
"195.200.70.*40*", "/04 LV gelieferte Daten 04_2010/04 LV 
Seiten/Jungz?chter"
Wed Mar 10 15:52:33 2010 [pid 15231] [uploaduser] FAIL MKDIR: Client 
"195.200.70.*41*", "/04 LV gelieferte Daten 04_2010/04 LV 
Seiten/Jungz?chter"
Wed Mar 10 15:52:36 2010 [pid 15232] [uploaduser] OK UPLOAD: Client 
"195.200.70.*40*", "/04 LV gelieferte Daten 04_2010/04 LV 
Seiten/Jungz?chter/Kooperationsseminar.doc", 23552 bytes, 13.89Kbyte/sec
Wed Mar 10 15:52:37 2010 [pid 15231] [uploaduser] OK UPLOAD: Client 
"195.200.70.*41*", "/04 LV gelieferte Daten 04_2010/04 LV 
Seiten/Jungz?chter/Veranstaltungen der Jungz?chter im Jahr 2010.doc", 
23552 bytes, 9.07Kbyte/sec
Wed Mar 10 15:52:38 2010 [pid 15232] [uploaduser] OK UPLOAD: Client 
"195.200.70.*40*", "/04 LV gelieferte Daten 04_2010/04 LV 
Seiten/Jungz?chter/Foto Kooperationsseminar von laura weber.JPG", 13445 
bytes, 9.90Kbyte/sec


What I am concerned about is the fact that the client sends out using 
various gateways at once. Is there some configuration item in VSFTPD 
which can prevent this and reject packets from the additional ip addresses?


Any hint or help is appreciated.

Dirk


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