Denial of service - CPU loop

2014-06-2300:00:00

Samba Security

www.samba.org

522

3.3 Low

CVSS2

Attack Vector

ADJACENT_NETWORK

Attack Complexity

LOW

Authentication

NONE

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

PARTIAL

AV:A/AC:L/Au:N/C:N/I:N/A:P

0.084 Low

EPSS

Percentile

94.4%

JSON

Description

All current released versions of Samba are vulnerable to a denial of
service on the nmbd NetBIOS name services daemon. A malformed packet
can cause the nmbd server to loop the CPU and prevent any further
NetBIOS name service.

This flaw is not exploitable beyond causing the code to loop
expending CPU resources.

Patch Availability

A patch addressing this defect has been posted to

http://www.samba.org/samba/security/

Additionally, Samba 4.1.9, 4.0.19 and 3.6.24 have been issued as
security releases to correct the defect. Patches against older Samba
versions are available at http://samba.org/samba/patches/. Samba
vendors and administrators running affected versions are advised to
upgrade or apply the patch as soon as possible.

Workaround

None.

Credits

This problem was found by a Red Hat user and analyzed by
Stefan Cornelius <[email protected]>. Jeremy Allison of Google
provided the Samba code fix for nmbd.