Zero-Day Windows Security Flaw Can Crash Systems, Cause BSODs (helpnetsecurity.com)

Orome1 quotes a report from Help Net Security: A zero-day bug affecting Windows 10, 8.1, Windows Server 2012 and 2016 can be exploited to crash a vulnerable system and possibly even to compromise it. It is a memory corruption bug in the handling of SMB traffic that could be easily exploited by forcing a Windows system to connect to a malicious SMB share. Tricking a user to connect to such a server should be an easy feat if clever social engineering is employed. The vulnerability was discovered by a researcher that goes by PythonResponder on Twitter, and who published proof-of-exploit code for it on GitHub on Wednesday. The researcher says that he shared knowledge of the flaw with Microsoft, and claims that "they had a patch ready 3 months ago but decided to push it back." Supposedly, the patch will be released next Tuesday. The PoC exploit has been tested by SANS ISC CTO Johannes Ullrich, and works on a fully patched Windows 10. "To be vulnerable, a client needs to support SMBv3, which was introduced in Windows 8 for clients and Windows 2012 on servers," he noted, and added that "it isn't clear if this is exploitable beyond a denial of service." Until a patch is released, administrators can prevent it from being exploited by blocking outbound SMB connections (TCP ports 139 and 445, UDP ports 137 and 138) from the local network to the WAN, as advised by CERT/CC. "The tweet originally announcing this issue stated that Windows 2012 and 2016 is vulnerable," the researcher said. "I tested it with a fully patched Windows 10, and it got an immediate blue screen of death."

Comments

"It's a Bird... It's a Plane... It's SMB!"

[weedjams]

sry, been drinkin' since noon. *grin* game on all and be safe.

Yet another reason...

[LVSlushdat]

Yet another reason, if we really *need* another, to quit using MS products. I used/supported MS products for 20 years as a sysadmin, but when I retired in 2010, I decided I was done with Windows on my personal systems. I had been dualbooting Win7 and Linux, but once I made the decision, I simply deleted the Win7 partition, and reinstalled grub. After 6 years of zero MS, I've not missed it a bit.. In fact, I'm forced to use Windows in a part-time volunteer support position with a local charity, and I find that using Windows now, after being 100% Linux for going on 7 years, is very unnatural. After seeing all of the multiple forms of abuse MS heaps on those who still use Windows, I couldn't be happier with my decision...

Re:Our Windows Server 2012 R2 servers have been...

[cavreader]

Crashing all day? I suggest getting a book or taking a class on how to install and configure 2012 servers. Or maybe just get someone who knows what the hell they are doing to setup your server(s). The #1 cause of server exploits in both Windows and Linux OS's are the idiot administrators.

Stupid

[duke_cheetah2003]

Attacking SMB is retarded. SMB services should -never- ever be exposed to the internet, under any circumstances. Anyone who does expose SMB to the internet deserves to get hacked. Bury that crap in a VPN, use a firewall, and disregard this silliness.

Re:Stupid

[Lord Crc]

SMB services should -never- ever be exposed to the internet, under any circumstances.

If it's like the last SMB issue, then the issue is not that they send packets to an SMB server, but rather get the machine to connect (outbound) to a malicious SMB server, which replies with malicious packets.

This can be done using standard phishing tricks.

This is why one should block outbound SMB traffic as well.

Re:Stupid

[140Mandak262Jamuna]

What if the night janitor is bribed to plug in an usb dongle to some exposed usb port in some machine?

Irresponsible disclosure

[Etcetera]

Regardless of whether they pushed it back or not, if they're planning to release next Tuesday then disclosing the hole with PoC exploit code is just irresponsible. You could have waited 5 more days.

Re: Irresponsible disclosure

[subk]

Make sure your SMB is behind a firewall.

RTFA: It is not an attack on your SMB. It's a phishing-style attack vector that tricks users into contacting a malicious server. More appropriately, one should block outbound SMB traffic to "not your SMB".

Where's my villain mustache and hat?

[bheerssen]

I have an SMB server on my network and I think I just found a way to convince my family to switch to Linux.