It was discovered the Samba handled symlinks in an unexpected way when both “wide links” and “UNIX extensions” were enabled, which is the default. A remote attacker could create symlinks and access arbitrary files from the server.
The problem can be corrected by updating your system to the following package versions:
24 March 2010
A security issue affects these releases of Ubuntu and its derivatives:
It was discovered the Samba handled symlinks in an unexpected way when both “wide links” and “UNIX extensions” were enabled, which is the default. A remote attacker could create symlinks and access arbitrary files from the server.
The problem can be corrected by updating your system to the following package versions:
To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.
In general, a standard system upgrade is sufficient to effect the necessary changes.
ATTENTION: This update changes the default samba behaviour. For security reasons, it is no longer possible to use wide links and UNIX extensions at the same time. After applying this security update, wide links will be disabled automatically as UNIX extensions are turned on by default. If wide links are required, you can re-enable them by adding “unix extensions = no” to the [global] section of the /etc/samba/smb.conf configuration file.
Vulmon