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Date: Thu, 16 Feb 2012 16:05:26 -0700
From: Kurt Seifried <>
CC: Ludwig Nussel <>, Vincent Untz <>
Subject: Re: CVE request: mumble local information disclosure

On 02/16/2012 07:35 AM, Ludwig Nussel wrote:
> Vincent Danen wrote:
>> It was discovered that mumble created its database file
>> (~/.local/share/data/Mumble/.mumble.sqlite) with insecure world-readable
>> permissions.  If the user had (non-default) permissions on their home
>> directory, another local user could obtain password and configuration
>> settings from the database file.
> It certainly makes sense for cautios applications to make sure sensitive
> settings have restricted access permissions. Question is whether it is
> actually a vulnerability if they don't. Quoting the XDG specĀ¹

We can't rely upon file permissions being done safely/properly, just
like we can't rely upon proper firewalls/etc for network services that
"should" be internal only but sometimes are not (e.g.
SMB/CIFS/NFS/etc.), There are often very legitimate cases for not having
a firewall, world readable home dir, etc. The whole onion (multi-layered
security) approach and so forth means we classify a lot more things as
security vulns than is perhaps strictly necessary, but in the long run
leads to safer and more robust systems.

> | If, when attempting to write a file, the destination directory is
> | non-existant an attempt should be made to create it with permission
> | 0700. If the destination directory exists already the permissions should
> | not be changed.
> So it could be argued that mumble just relied on the specification that
> already mandates restrictive permissions on ~/.config.

The specifications might be wrong, they might be incomplete, they might
be interpreted incorrectly, they might be implemented incorrectly, etc.

> The program that is supposed to create ~/.config on login had a bug that
> made the dir 755 in violation of the specĀ². Fixing the permissions is
> not allowed according to the spec though ...
> cu
> Ludwig
> [1]
> [2]

Kurt Seifried Red Hat Security Response Team (SRT)

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