Three Major Security Flaws in the Frame-Capture Based Graphics Debugger RenderDoc

RenderDoc, a frame-capture-based graphics debugger, designed to streamline the development process on platforms such as Vulkan, D3D11, D3D12, OpenGL, and OpenGL ES, has recently been under the cyber-security spotlight. Operating across multiple platforms like Windows, Linux, Android, and Nintendo Switch™, RenderDoc has cultivated a reputation for aiding in debugging proprietary programs. Though this open-source tool is not intended for capturing commercial games or applications not developed by the user, it remains a potent tool for developers.

However, behind the facade of this versatile tool, three major security vulnerabilities have recently been unearthed by vigilant security researchers from Qualys. These findings highlighted serious flaws that could potentially lead to privilege escalation and remote code execution, revealing the latent threats that had been lurking within RenderDoc’s framework.

One of the most glaring vulnerabilities, dubbed CVE-2023-33865, is a symlink flaw that an unprivileged local attacker could exploit to acquire the privileges of the user running RenderDoc. This weakness exposes the user to potentially harmful entities, opening up a channel for illicit activities.

Next on the list, CVE-2023-33864 is an integer underflow that results in a heap-based buffer overflow within RenderDoc’s server thread on TCP port 38920. With just a carefully engineered handshake packet using the client name parameter, a remote attacker can exploit this vulnerability, giving them the ability to execute arbitrary code on the target machine.

Lastly, CVE-2023-33863, an integer overflow, also results in a heap-based buffer overflow within RenderDoc’s server thread. Similar to its predecessor, this vulnerability also has the potential to be exploited by a remote attacker, enabling them to execute arbitrary code on the affected machine.

These vulnerabilities were brought to light following the release of the technical detail and proof-of-concept by the researchers. They highlighted how an otherwise innocuous debugging tool could harbor serious security threats, potentially leading to devastating consequences.

Fortunately, the vigilant RenderDoc community swiftly rectified these vulnerabilities, issuing fixes on May 19, 2023. Thus, RenderDoc versions v1.27 and beyond are now secure, while v1.26 and prior remain vulnerable.

RenderDoc’s TCP port 39920, restricted to connections from private IPs, has additional configuration options to enhance its security further. Conversely, the TCP port 38920, which was more susceptible due to its unrestricted access, lacked these configuration options. This highlighted the pressing need for a more robust security framework within RenderDoc’s network configurations.