| 1 |
>>>>> And if I pull, none of my backed-up systems are secure because anyone |
| 2 |
>>>>> who breaks into the backup server has root read privileges on every |
| 3 |
>>>>> backed-up system and will thereby "gain full root privileges quickly." |
| 4 |
>>>> |
| 5 |
>>>> IMO that depends on whether you also backup the authentication-related |
| 6 |
>>>> files or not. Exclude them from backup, ensure different root passwords |
| 7 |
>>>> for all boxes, and now you can limit the infiltration. |
| 8 |
>>> |
| 9 |
>>> If you're pulling to the backup server, that backup server has to be |
| 10 |
>>> able to log in to and read all files on the other servers. Including |
| 11 |
>>> e.g. your swap partition and device files. |
| 12 |
>> |
| 13 |
>> What if I have each system save a copy of everything to be backed up |
| 14 |
>> from its own filesystem in a separate directory and change the |
| 15 |
>> ownership of everything in that directory so it can be read by an |
| 16 |
>> unprivileged backup user? Then I could have the backup server pull |
| 17 |
>> that copy from each system without giving it root access to each |
| 18 |
>> system. Can I somehow have the correct ownerships for the backup |
| 19 |
>> saved in a separate file for use during a restore? |
| 20 |
>> |
| 21 |
>> - Grant |
| 22 |
>> |
| 23 |
> |
| 24 |
> You could just as well use an NFS share with no_root_squash. It is |
| 25 |
> really more a question of finding the right combination of tools to |
| 26 |
> ensure proper separation of concern for server and client. |
| 27 |
> |
| 28 |
> In fact, I think we are intermixing three distinct problems: |
| 29 |
> 1. (Possible) limitations of rdiff-backup with regard to untrusted |
| 30 |
> backup servers or clients. |
| 31 |
|
| 32 |
The limitation is real unfortunately. All backups created by |
| 33 |
rdiff-backup more than a second ago can be deleted something like |
| 34 |
this: |
| 35 |
|
| 36 |
rdiff-backup --remove-older-than 1s backup@12.34.56.78::/path/to/backup |
| 37 |
|
| 38 |
> 2. The purely technical question which file transfer protocols protect |
| 39 |
> against write access from backup server to backup client and backup |
| 40 |
> client to older backups on the server. |
| 41 |
|
| 42 |
rdiff-backup doesn't provide those sort of protections. Do any file |
| 43 |
transfer protocols? |
| 44 |
|
| 45 |
> 3. The more or less organisational question what level of protection |
| 46 |
> backups need and how fast security breaks have to be detected. |
| 47 |
|
| 48 |
I think backups should be very well protected and security breaks |
| 49 |
should not have to be immediately detected. |
| 50 |
|
| 51 |
- Grant |
| 52 |
|
| 53 |
|
| 54 |
> I think push vs. pull is just a secondary concern with regard to the |
| 55 |
> second question and has practically no relevance to the third one. |
| 56 |
> |
| 57 |
> Regards, |
| 58 |
> Florian Philipp |
Archives