CVE-2023-28252

This is a Windows “privilege escalation” flaw: if an attacker already has a foothold with low permissions on a computer, they can use it to become far more powerful (like taking over admin-level abilities). Think of it like someone already inside your building finding a master key to every office—turning a small break-in into full control. It’s been flagged by CISA as part of ransomware activity, which is why it matters for business systems.

This matters if you run Windows 10, Windows 11, or any of the listed Windows Server versions on computers that could be reached by an attacker (for example, machines that can be compromised through phishing, exposed remote access, weak passwords, or other security gaps). The flaw is local and requires low privileges, meaning it’s primarily a risk after an attacker has already gotten onto the system or otherwise gained some access. CISA’s KEV indicates it was used in ransomware campaigns, so you should assume it’s reachable in real attacks once attackers have a local foothold.

This is RED because CISA has confirmed real-world use in ransomware campaigns. Attackers can leverage this after obtaining low-level access on a Windows machine, turning that foothold into higher privileges without needing the end user to do anything. Patch as soon as possible following Microsoft’s guidance for CVE-2023-28252.

1. Inventory and identify exposure

   • Confirm which devices in your environment run: Windows 10, Windows 11, and Windows Server 2008/2008 R2/2012/2012 R2/2016/2019/2022.
   • For each device, capture the OS build/version so you can compare against the fixed versions provided by Microsoft.

2. Confirm patch status against the fixed versions

   • Windows 10 fixed builds include: 10.0.10240.19869; 10.0.14393.5850; 10.0.17763.4252; 10.0.19042.2846; 10.0.19044.2846; 10.0.19045.2846.
   • Windows 11 fixed builds include: 10.0.22000.1817; 10.0.22621.1555.
   • Windows Server fixed builds include:
     • 2008: 6.0.6003.22015
     • 2012: 10.0.14393.5850
     • 2016: 10.0.14393.5850
     • 2019: 10.0.17763.4252
     • 2022: 10.0.20348.1668
   • If a device’s build is below the fixed build for its branch, it should be considered vulnerable.

3. Apply the vendor update

   • Use Microsoft’s update guidance page for CVE-2023-28252 and install the recommended updates for your specific OS branch.
   • After installation, re-check the build/version to ensure it matches or exceeds the fixed value(s) above.

4. Temporary workaround (if patching is delayed)

   • Because this is a local elevation-of-privilege issue (local attacker with low privileges), the safest “stopgap” is to reduce the chance of an attacker gaining low privileges in the first place:
     • Treat all suspicious endpoints as high priority for investigation.
     • Enforce strong account controls (password hygiene, minimize local admin usage, disable unnecessary accounts/services).
   • Note: these steps reduce risk but do not replace installing the fixed updates.

5. Prioritize based on CISA KEV / ransomware likelihood

   • CISA lists this CVE as used in ransomware campaigns and provided a remediation due date of 2023-05-02.
   • Prioritize systems that are internet-facing, regularly accessed by staff, or have higher exposure to phishing/remote-access compromise.

6. Monitoring after patching

   • Watch for signs of compromise on endpoints (unusual process activity, unexpected privilege changes, and abnormal authentication behavior). If you detect compromise indicators, assume additional post-compromise actions may have already occurred and respond accordingly.

Severity is High (CVSS 7.8). The weakness is an elevation-of-privilege issue (CWE-122; CWE-787) in the Windows Common Log File System Driver. The attack vector is local and requires low privileges, with no user interaction, meaning it can be used by an attacker after gaining some foothold on the machine. CISA KEV confirms it has been used in ransomware campaigns (added 2023-04-11) and lists remediation guidance with a due date of 2023-05-02. A public exploit is available (weaponized), which increases practical risk once an attacker has local access. EPSS was predicted at 49.0% with a falling trend, but KEV confirmation takes precedence for urgency. “KEV” here means CISA cataloged the vulnerability as being exploited in real incidents, not just theoretically possible.