Critical Vulnerability Alert in Samba - CVE-2021-44142


We would like to bring your attention to the following Critical vulnerability we have recently become aware of.


All versions of Samba prior to 4.13.17 are vulnerable to an out-of-bounds heap read write vulnerability that allows remote attackers to execute arbitrary code as root on affected Samba installations that use the VFS module vfs_fruit. To exploit this vulnerability a user that has write access to a file's extended attributes is required, this user could be a guest or unauthenticated user if these users were configured to allow write access to file extended attributes.


Remediation


Patches have been released by samba.org to address this vulnerability and should be applied as soon as possible to mitigate any risk.


Patches can be found here:

The following mitigations are recommended to be applied if it is not possible to apply the samba patches immediately:


Remove the "fruit" VFS module from the list of configured VFS objects in any "vfs objects" line in the Samba configuration smb.conf.


Note that changing the VFS module settings fruit:metadata or fruit:resource to use the unaffected setting causes all stored information to be inaccessible and will make it appear to macOS clients as if the information is lost.


We are actively monitoring the situation.


References: