Information Security News
Developers of Samba 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, 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 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.
Xavier Mertens (@xme)
ISC Handler - Freelance Security Consultant
Maintainers of the Samba networking utility just patched a critical code-execution vulnerability that could pose a severe threat to users until the fix is widely installed.
The seven-year-old flaw, indexed as CVE-2017-7494, can be reliably exploited with just one line of code to execute malicious code, as long as a few conditions are met. Those requirements include vulnerable computers that (a) make file- and printer-sharing port 445 reachable on the Internet, (b) configure shared files to have write privileges, and (c) use known or guessable server paths for those files. When those conditions are satisfied, remote attackers can upload any code of their choosing and cause the server to execute it, possibly with unfettered root privileges, depending on the vulnerable platform.
"All versions of Samba from 3.5.0 onwards are vulnerable to a remote code execution vulnerability, allowing a malicious client to upload a shared library to a writable share, and then cause the server to load and execute it," Samba maintainers wrote in an advisory published Wednesday. They urged anyone using a vulnerable version to install a patch as soon as possible.