Concerned About Your Business Cyber Security?

(877) 321--7374

Critical Vulnerability in Samba from 3.5.0 onwards, (Thu, May 25th)

Developers of Samba[1] disclosed a critical vulnerability that affects the file sharing component. Samba is a suite of tools that helps in the interoperability between UNIX with Microsoft Windows. The vulnerable component is the daemon that offers file sharing capabilities.

As reported by HD Moore on his Twitter account[2], its trivial to trigger the vulnerability(just a one-liner exploit). An attacker has to find an open SMB share (TCP/445), padding:5px 10px”>
nt pipe support = no

to the [global] section of your smb.conf and restart smbd.

Samba is a very popular tool and used on many corporate networks, it is also a core component in many residential products like NAS. Many vendors could be affected (Synology, WD, Qnap, DLink, …). Some vendors like Synology[5] already communicated about this issue and are working on a patch but others might take more time to react. Home users do not patch their products and many NAS could remain vulnerable for a long time.

As always, if you are exposing writable SMB shares for your users, be sure to restrict access to authorisedpeople/hosts and do NOT share data across the Internet. They are risks that bad guys are already scanning the whole Internet.

[1]https://www.samba.org/
[2]https://twitter.com/hdmoore/status/867446072670646277
[3]https://www.samba.org/samba/security/CVE-2017-7494.html
[4]http://www.samba.org/samba/security/
[5]https://www.synology.com/en-global/support/security/Important_Information_Regarding_Samba_Vulnerability_CVE_2017_7494

Xavier Mertens (@xme)
ISC Handler – Freelance Security Consultant
PGP Key

(c) SANS Internet Storm Center. https://isc.sans.edu Creative Commons Attribution-Noncommercial 3.0 United States License.

Ready For ASuperheroI.T. Solution?

Real Time Web Analytics