[OpenAFS-devel] Lockdown for VL and VOL RPC interfaces for non-authenticated user

[Jeffrey Altman]

This is a cryptographically signed message in MIME format.

--------------ms020200020004060001030602
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: quoted-printable

Gergely,

I'm going to prune the majority of the content because I would like to
focus on the threats you wish to protect against.

On 3/15/2014 3:33 PM, Gergely Risko wrote:
[...]

You have proposed a mechanism for locking down some of the RPCs on the
VOL and VL services based upon:

  system:anyuser (the current behavior)

  system:authuser

  system:administrator

I believe that such broad controls on the RPCs that are not used by the
cache managers are reasonable.  Doing so will not violate the agreement
with IBM on the use of the AFS protocol.  However, I'm not sure that
doing so will address your specific threats.

I also believe there needs to be an additional level to permit
system:authuser + authenticated foreign users.

[...]

> I think this leak is significant to be bothering:
>   - spammers can get valid email addresses,

There are a variety of methods by which spammers do this today:

1. They scan the contents of the "home", "usr", "user", etc. tree in the
   cell's file system name space.   The list of mount points is more
   often then not system:anyuser "l" or at best system:authuser "l"
   in order to permit users to see each others home directories and
   because machines they login into must be able able to access the
   home directories before the user's authentication tokens have been
   obtained.

2. "vos listvldb" can be used to obtain the list of all volumes.  The
   user names can often be extracted from the volume names.

3. "vos listaddr" to obtain the list of all file servers combined with
   "vos listvol" can be used to obtain a list of all volume names.

There is little benefit to locking down the vlserver and the volserver
if the file system can be searched.

>   - spammers can confirm based on the stats the list of users that are
>     actually active on a computer system,

The cache manager debug interface (cmdebug) is implemented by all
existing AFS cache managers.  This interface can be used to obtain the
list of FIDs in the cache including the active set of callbacks.  The
FIDs indicate the cell and the volume by ID.  The ID can be converted to
a volume name using VL_GetEntryByName*() RPCs that must be open to
permit cache managers to lookup the file server/partitions on which a
volume is located.

The "vos examine" reported statistics are not necessary.   There is no
authentication on the cache manager debugging interface because there is
no mechanism for keying the service.   The "volume stats" also are not
collected for a specific "computer or device" but for the cell as a whole=
=2E

>   - from the vol stats people can monitor and figure out if someone is
>     at the computer using AFS which can be part of a bigger social
>     attack or harrasment scenarios.

The volume statistics can indicate which volumes are more actively used.

[...]

Jeffrey Altman



--------------ms020200020004060001030602
Content-Type: application/pkcs7-signature; name="smime.p7s"
Content-Transfer-Encoding: base64
Content-Disposition: attachment; filename="smime.p7s"
Content-Description: S/MIME Cryptographic Signature
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=
--------------ms020200020004060001030602--