CVE-2019-10197: Path Traversal
A flaw was found in samba versions 4.9.x up to 4.9.13, samba 4.10.x up to 4.10.8 and samba 4.11.x up to 4.11.0rc3, when certain parameters were set in the samba configuration file. An unauthenticated attacker could use this flaw to escape the shared directory and access the contents of directories outside the share.
Other sources
As per upstream advisory:
On a Samba SMB server for all versions of Samba from 4.9.0 clients are able to escape outside the share root directory if certain configuration parameters set in the smb.conf file.
The problem is reproducable if the 'wide links' option is explicitly set to 'yes' and either 'unix extensions = no' or 'allow insecure wide links = yes' is set in addition.
If a client has no permissions to enter the share root directory it will get ACCESSDENIED on the first request. However smbd has a cache that remembers if it successfully changed to a directory. This cache was not being reset on failure. The following SMB request will then silently operate in the wrong directory instead of returning ACCESSDENIED. That directory is either the share root directory of a different share the client was operating on successfully before or the global root directory ('/') of the system.
The unix token (uid, gid, list of groups) is always correctly impersonated before each operation, so the client is still restricted by the unix permissions enfored by the kernel.
— Red Hat
Affected Software
Event History
Frequently Asked Questions
What versions of Samba are affected by CVE-2019-10197?
Samba versions 4.9.x up to 4.9.13, 4.10.x up to 4.10.8, and 4.11.x up to 4.11.0rc3 are affected by CVE-2019-10197.
What is the severity of CVE-2019-10197?
CVE-2019-10197 has a high severity rating due to its potential to allow unauthorized access to sensitive directories.
How do I fix CVE-2019-10197?
To fix CVE-2019-10197, upgrade Samba to version 4.9.14 or higher, 4.10.9 or higher, or 4.11.1 or higher.
Can CVE-2019-10197 be exploited remotely?
Yes, CVE-2019-10197 can be exploited remotely by an unauthenticated attacker.
What type of attack does CVE-2019-10197 enable?
CVE-2019-10197 enables attackers to escape the shared directory and access files on the underlying file system.