Recently, Microsoft silently addressed a significant vulnerability related to device isolation
in Defender for Endpoint. This fix prevents isolated devices from bypassing network restrictions
using techniques such as WSL (Windows Subsystem for Linux) and SOCKS5 proxies.
While this is a positive step towards enhancing security, other critical issues remain unaddressed.
Conditional Access: Despite the fix for device isolation, the conditional access policies still have
loopholes that can be exploited. These policies are crucial for ensuring that only compliant devices
can access corporate resources, and any vulnerabilities here can pose significant risks.
Web Content Filtering: Another area that requires attention is web content filtering.
Currently, there are gaps in the filtering mechanisms that allow users to access restricted content.
This can lead to exposure to malicious websites and other security threats.
Proxy (Tor): Similar to using an external proxy, it is still possible to use a Tor proxy in WSL.
By installing and starting the Tor SOCKS5 proxy, users can bypass network restrictions and access
otherwise restricted and blocked sites.
This method is not caught by security logs, posing a significant risk.
The Microsoft Security Response Center (MSRC) has been notably unresponsive and uncooperative
regarding these issues.
Despite multiple reports and requests for assistance, there has been little to no communication
or action from MSRC.
This lack of responsiveness is concerning and highlights the need for more proactive engagement from
Microsoft in addressing security vulnerabilities.
While the fix for device isolation is a step in the right direction, Microsoft needs to address
the remaining vulnerabilities in conditional access, web content filtering, and proxy usage.
Additionally, improved responsiveness and cooperation from MSRC are essential for maintaining
trust and ensuring the security of their products.