A local user without admin rights could:
Alternatively, the attacker could use C:\Program Files\Active.exe as the hijack target.
Overview Active Webcam is a popular software solution by Pysoft used for video surveillance and security camera management. In version 11.5 (and potentially earlier iterations), the software was discovered to contain a classic Windows configuration vulnerability known as an Unquoted Service Path.
This vulnerability is categorized as a Local Privilege Escalation (LPE). It allows a low-privileged local user to execute arbitrary code with elevated privileges (typically SYSTEM), effectively granting them full control over the affected machine.
Technical Breakdown
The vulnerability stems from how the Windows Service Control Manager (SCM) handles file paths containing spaces.
The Mechanism: When Windows attempts to start this service, the SCM parses the unquoted string from left to right. Because the path is unquoted and contains spaces, the SCM interprets the space as a break between the executable and its arguments. It attempts to execute the first valid executable it finds in the following order:
The Exploitation:
By default, the C:\Program Files directory is write-protected for standard users. However, if a subfolder (like Active Webcam) has weak permissions—or if the attacker targets a path structure where they have write access—they can place a malicious executable named to match the truncated path (e.g., naming a malicious file Active.exe and placing it in C:\Program Files\Active Webcam\). active webcam 115 unquoted service path patched
When the computer restarts or the service is restarted, Windows locates the malicious Active.exe first, executes it with SYSTEM privileges, and compromises the machine.
The Patch and Resolution
The "patch" for this vulnerability is deceptively simple but critical for security hygiene.
Why This Remains Interesting
While this is a "low-complexity" vulnerability compared to memory corruption exploits (like buffer overflows), it remains a fascinating case study for several reasons:
Conclusion The Unquoted Service Path vulnerability in Active Webcam 115 serves as a reminder that security is not just about writing secure code logic, but also about secure configuration management. It emphasizes the importance of rigorous quality assurance during the software installation phase to ensure that the operating system interprets file paths exactly as the developer intended.
The unquoted service path vulnerability in Active WebCam 11.5 Apply Least Privilege principle – Services should run
(identified as CVE-2021-47790) represents a significant security risk that allows local attackers to execute arbitrary code with elevated system privileges. This vulnerability arises from a misconfiguration in how the software registers its executable path within the Windows operating system. The Mechanics of the Vulnerability
In Windows, when a service is installed with a file path containing spaces (e.g., C:\Program Files\Active WebCam\WebCam.exe
) and is not enclosed in double quotes, the operating system interprets the spaces as separators. An attacker with local write permissions can place a malicious executable at a higher-level directory—such as C:\Program.exe
—which Windows will then execute instead of the intended service file during system startup. Because services like Active WebCam often run with LocalSystem
or administrative privileges, this exploit results in a full privilege escalation for the attacker. National Institute of Standards and Technology (.gov) Vulnerability Details Software Version : Active WebCam 11.5. Vulnerability Type : Local Privilege Escalation via Unquoted Service Path. Affected Path : Typically C:\Program Files\Active WebCam\WebCam.exe Primary Risk
: Attackers gaining administrative or SYSTEM access to the machine. Patching and Remediation
While official patches for legacy software may be limited, users can manually "patch" or remediate this vulnerability by editing the Windows Registry to secure the service path. InfoSec Governance A local user without admin rights could:
Potential Exploitation of an Unquoted Service Path Vulnerability - Elastic
Here’s a structured content piece for a security advisory or blog post titled “Active WebCam 115 – Unquoted Service Path Patched”:
The ActiveWebCamService in versions prior to the patch references an executable path containing spaces without enclosing quotes. For example:
C:\Program Files\Active WebCam\webcam.exe
Due to the missing quotes, Windows interprets the path as:
A local attacker with the ability to write to a writable directory early in the search sequence (e.g., C:\Program.exe) can execute arbitrary code with SYSTEM privileges when the vulnerable service starts.
Estimated CVSS 3.1 Base Score: 7.8 (High)