Last weekend a security researcher publically disclosed a zero-day vulnerability in Windows 10, Windows 8.1 and Server editions after Microsoft failed to patch it in the past three months.
The zero-day memory corruption flaw resides in the implementation of the SMB (server message block) network file sharing protocol that could allow a remote, unauthenticated attacker to crash systems with denial of service attack, which would then open them to more possible attacks.
According to US-CERT, the vulnerability could also be exploited to execute arbitrary code with Windows kernel privileges on vulnerable systems, but this has not been confirmed right now by Microsoft.
Without revealing the actual scope of the vulnerability and the kind of threat the exploit poses, Microsoft has just downplayed the severity of the issue, saying:
“Windows is the only platform with a customer commitment to investigate reported security issues, and proactively update impacted devices as soon as possible. We recommend customers use Windows 10 and the Microsoft Edge browser for the best protection.”
However, the proof-of-concept exploit code, Win10.py, has already been released publicly for Windows 10 by security researcher Laurent Gaffie and does not require targets to use a browser.
The memory corruption flaw resides in the manner in which Windows handles SMB traffic that could be exploited by attackers; all they need is tricking victims to connect to a malicious SMB server, which could be easily done using clever social engineering tricks.