| 2013-03-12 16:04:17 |
Alvaro Lopez |
description |
The Xen drivers split a string to create an array for subprocess.Popen, rather than passing an array directly. This invites the potential for command injection / manipulation.
There is no clearly valid reason to use string splitting here when arguments can be passed, as elsewhere, directly into Popen.
The behavior here is present in current Trunk, Folsom, and Essex. Per Trunk and Folsom, _rsync_vhds calls plugins.utils.subprocess to perform the splitting. In Essex, this behaviorism was present directly in migration/transfer_vhd.py, rather than in utils.py. Earlier releases have not been evaluated.
I am not certain if this is directly exploitable. The user field is inserted into the generated strings used for command-line execution, and it does seem that Keystone allows usernames to contain arbitrary tokens/characters such as spaces. It is not clear to me if the user field directly matches that in Keystone, if the user field is otherwise validated in the API, etc. Other fields inserted into the command string seem to be internally generated. |
The XenApi drivers split a string to create an array for subprocess.Popen, rather than passing an array directly. This invites the potential for command injection / manipulation.
There is no clearly valid reason to use string splitting here when arguments can be passed, as elsewhere, directly into Popen.
The behavior here is present in current Trunk, Folsom, and Essex. Per Trunk and Folsom, _rsync_vhds calls plugins.utils.subprocess to perform the splitting. In Essex, this behaviorism was present directly in migration/transfer_vhd.py, rather than in utils.py. Earlier releases have not been evaluated.
I am not certain if this is directly exploitable. The user field is inserted into the generated strings used for command-line execution, and it does seem that Keystone allows usernames to contain arbitrary tokens/characters such as spaces. It is not clear to me if the user field directly matches that in Keystone, if the user field is otherwise validated in the API, etc. Other fields inserted into the command string seem to be internally generated. |
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