CVE-2022-43552 Windows: Patch Now to Block Zero-Day Print Spooler Exploits

Windows systems running unpatched versions are under attack through CVE-2022-43552, a zero-day flaw in the Print Spooler service that lets hackers execute code remotely.

Your network could already be compromised if you haven’t applied Microsoft’s emergency fixes—this exploit doesn’t need user interaction to take hold. Attackers are actively weaponizing it, and the stakes couldn’t be higher for businesses or home users with shared printers.

This isn’t just another update; it’s a critical security bulletin that shuts down remote code execution by patching the vulnerable spoolss.dll component. Microsoft’s KB5017303 and KB5017302 fixes address the flaw, but many systems remain exposed because admins haven’t prioritized the patch.

Below, I’ll walk you through how to verify if your Windows machine is protected, apply the fix if needed, and implement temporary safeguards while you wait. Don’t skip this—your data depends on it.

What is CVE-2022-43552 and why is it so dangerous?

CVE-2022-43552 is a critical zero-day vulnerability in Windows' Print Spooler service (spoolss.dll), allowing attackers to execute remote code execution (RCE) without user interaction. Unlike previous Print Spooler flaws, this exploit doesn’t require local access—just a maliciously crafted print job over SMB or RPC. Microsoft confirmed no prior fixes existed when exploitation began in late 2022.

The vulnerability stems from a memory corruption flaw in how Windows processes print jobs. Attackers send a specially designed print ticket to trigger a buffer overflow in spoolss.dll, letting them escalate privileges or drop malware.

This is a wormable exploit, meaning it can spread laterally across networks like EternalBlue (used in WannaCry).

Real-world attacks have targeted unpatched Windows 10/11 and Windows Server 2019/2022 systems, with threat actors like APT groups and ransomware operators exploiting it. The MITRE ATT&CK framework classifies this as T1059.001 (Command-Line Interface) exploitation, often leading to full system compromise.

What makes this worse? The exploit doesn’t trigger User Account Control (UAC) prompts, so malicious code runs silently with SYSTEM-level privileges. Attackers can then deploy Cobalt Strike beacons, ransomware, or data-stealing malware without detection until it’s too late.

Microsoft classified this as a critical severity vulnerability (CVSS 9.8) due to its remote, unauthenticated nature. The Print Spooler service is enabled by default on most Windows systems, making it a prime target.

Unlike PrintNightmare (CVE-2021-1675), which required local admin rights, this exploit works over network shares, increasing attack surface.

Cybersecurity firms like CrowdStrike and FireEye reported active exploitation campaigns in Q4 2022, with attackers using this to deploy QakBot and Emotet malware families. The lack of defense-in-depth measures (like SMB signing) makes this particularly dangerous in enterprise environments with lateral movement capabilities.

If your system is exposed, attackers can achieve full domain compromise in minutes. For example, a crafted print job sent to a Windows Server 2019 machine could grant an attacker Domain Admin rights, allowing them to deploy Golden Ticket attacks or encrypt data for ransom.

The Windows Event Logs may show no suspicious activity until the damage is done.

Microsoft’s emergency patches (KB5017303 for Windows 10/11, KB5017302 for Server) fix the spoolss.dll flaw by adding input validation for print tickets. However, organizations must apply these immediately, as exploits are publicly documented and being weaponized. Without patching, even firewalled systems are at risk if attackers gain internal access.

To check if you’re vulnerable, verify your spoolss.dll version via File Explorer (C:\Windows\System32\spoolss.dll). Pre-patch versions are typically 10.0.19041.1 or lower. If you’re running an older build, treat it as compromised until patched. This isn’t just another update—it’s a race against active attackers.

Step-by-step guide to patch CVE-2022-43552 on Windows systems

Microsoft released emergency updates to fix CVE-2022-43552, a zero-day exploit targeting the Windows Print Spooler service. This vulnerability allows attackers to execute remote code without authentication.

If your system is unpatched, follow these steps to apply the fixes and verify protection. KB5017303 covers Windows 10/11, while KB5017302 applies to Server 2019/2022.

Before patching, check your current spoolss.dll version—vulnerable systems typically run versions older than 10.0.19041.2364 or 10.0.20348.2364. Use File Explorer to navigate to C:\Windows\System32\spoolss.dll and right-click to verify the file properties. If the version is outdated, proceed immediately to patch.

⚠️ Critical: This exploit is actively used in attacks. Microsoft classifies it as a critical severity vulnerability, meaning unpatched systems are at high risk of compromise. Prioritize patching all affected devices in your network.

Get-ItemProperty -Path "HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\Component Based Servicing\Packages" -Name "PackageIdentity" | Select-String -Pattern "KB5017303"

If you encounter issues during patching, such as update failures or compatibility errors, use Windows Update Troubleshooter or check Microsoft’s known issues page for your OS version. For servers, test the patch in a non-production environment first to avoid disruptions.

After patching, monitor your systems for unusual print spooler activity or unexpected network connections. Use Windows Event Viewer to check for Event ID 6005 (service start) or 6006 (service stop) errors, which may indicate exploitation attempts.

For additional security, restrict SMB access and disable the Print Spooler service if it’s not required.