CVE-2021-4481: Dräger Protector Software Local Privilege Escalation Vulnerability

Technical summary

CVE-2021-4481 is a privilege escalation vulnerability in Dräger Protector Software prior to version 6.4.2, classified under CWE-732 (Incorrect Permission Assignment for Critical Resource). The root cause is insecure file system permissions that fail to restrict write access to critical application directories or loaded modules. An unauthenticated local attacker can leverage this misconfiguration to replace executable binaries or dynamically loaded modules with malicious code. Upon execution—potentially via user interaction or automatic loading—the injected code runs with NT SYSTEM privileges, providing complete system compromise. The CVSS 3.1 score of 8.2 (HIGH) reflects the local attack vector (AV:L), low complexity (AC:L), no privilege requirement (PR:N), and high impact on both integrity and availability, though confidentiality is not directly affected.

Business impact

Systems running vulnerable versions of Dräger Protector Software are exposed to complete endpoint compromise by any user or process with local file system access. In a healthcare or industrial setting where Dräger products are commonly deployed, this could enable lateral movement, deployment of persistent malware, ransomware staging, or sabotage of critical operations. Organizations cannot rely on standard privilege boundaries; an attacker with even unprivileged local access can escalate to administrator level and assume full control of the system. Regulatory and compliance implications depend on the sensitivity of data or processes managed by affected systems.

Affected systems

Dräger Protector Software versions prior to 6.4.2 are affected. The vendor and product information in the advisory should be consulted to determine your installed version and whether your deployment includes this software. Dräger products are prevalent in healthcare, pharmaceutical manufacturing, and other regulated industries where endpoint security is critical.

Exploitability

This vulnerability requires local access; remote exploitation is not possible. However, local exploitability is straightforward: no special privileges are needed at the outset (PR:N), and the attack is not complex (AC:L). User interaction (UI:R) may be required depending on how the replacement module or binary is triggered (e.g., waiting for automatic service restart or prompting the user to execute a file). The attack scope is changed (S:C), meaning compromise extends beyond the vulnerable component to other processes and the system at large. While not currently listed on CISA's Known Exploited Vulnerabilities (KEV) catalog, the simplicity of the exploit path and the high severity warrant immediate attention.

Remediation

Upgrade Dräger Protector Software to version 6.4.2 or later. This version addresses the insecure file system permissions by applying proper access controls to critical binaries and modules. Before upgrading, verify compatibility with your environment and test in a controlled setting. If immediate patching is not possible, restrict local access to affected systems to trusted users only, enforce strong authentication, monitor file system changes in application directories, and consider isolating the system from shared networks until the patch is applied.

Patch guidance

Contact Dräger or consult their official security advisory for download links and detailed installation instructions for version 6.4.2 and beyond. Verify the integrity of downloaded patches using any provided checksums or signatures. Plan upgrades during maintenance windows to minimize operational disruption. Test patches on non-production instances first to confirm compatibility with your environment and dependent applications. After patching, verify that file system permissions on critical directories (particularly those containing executables and loaded modules) are now restrictive and do not permit unauthorized write access.

Detection guidance

Monitor for unauthorized modifications to Dräger Protector Software installation directories, particularly changes to executable files, DLLs, and module files. Use file integrity monitoring (FIM) solutions to alert on unexpected writes to sensitive application directories. Check file system permissions on Dräger-related directories and verify they are not world-writable or group-writable. Review access logs and process execution logs for any unexpected elevation to NT SYSTEM privileges, particularly when preceded by file system modifications. Compare running process hashes against known good baselines to detect binary replacement. In Windows environments, enable and audit object access logs for the Dräger installation directory.

Why prioritize this

Despite its local-only attack vector, this vulnerability merits high priority due to its ease of exploitation (low complexity, no special privilege requirement), complete system compromise potential (NT SYSTEM execution), and the scope of impact (affecting not just the application but the entire system and potentially downstream systems in an industrial or healthcare network). Organizations cannot achieve defense through network segmentation alone; internal threat actors and compromised accounts with local access become direct paths to full system takeover. The vulnerability is particularly urgent in multi-tenant or shared-access environments.

Risk score, explained

The CVSS 3.1 score of 8.2 (HIGH) appropriately reflects the severity. Local attack vector (AV:L) moderately constrains scope, but is not a limiting factor in many organizational contexts where multiple users or services run on the same systems. No privilege requirement (PR:N) and low complexity (AC:L) make exploitation trivial once local access is obtained. The changed scope (S:C) means the impact propagates beyond the vulnerable component. High integrity impact (I:H) and high availability impact (A:H) indicate that an attacker can alter system behavior and disrupt operations. Absence from the KEV catalog does not diminish risk; organizations should treat this as a high-priority remediation target based on their inventory of Dräger Protector deployments.

Frequently asked questions