CVE-2021-23169 in OpenEXR
Summary
by MITRE • 06/08/2021
A heap-buffer overflow was found in the copyIntoFrameBuffer function of OpenEXR in versions before 3.0.1. An attacker could use this flaw to execute arbitrary code with the permissions of the user running the application compiled against OpenEXR.
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Analysis
by VulDB Data Team • 06/11/2021
The heap-buffer overflow vulnerability CVE-2021-23169 resides within the OpenEXR library's copyIntoFrameBuffer function, representing a critical security flaw that affects versions prior to 3.0.1. This vulnerability demonstrates a classic memory corruption issue where insufficient bounds checking allows malicious input to overwrite adjacent memory locations within the heap allocation. The flaw specifically manifests when processing image data that exceeds expected buffer boundaries during frame buffer operations, creating opportunities for attackers to manipulate memory layout and execute arbitrary code. The vulnerability is classified under CWE-121 as a heap-based buffer overflow, where the buffer overflow occurs in heap memory rather than stack memory, making exploitation more complex but still highly dangerous.
The technical exploitation of this vulnerability occurs when an attacker crafts specially formatted OpenEXR image files that trigger the flawed copyIntoFrameBuffer function. During image processing, the application fails to validate input parameters against allocated buffer sizes, allowing data to be written beyond the intended memory boundaries. This memory corruption can overwrite critical data structures, function pointers, or return addresses, enabling attackers to redirect program execution flow. The vulnerability is particularly concerning because it operates within the context of applications that use OpenEXR libraries, meaning any software that processes OpenEXR image files becomes a potential attack vector. The exploitation requires the attacker to have the ability to provide malicious input to an application compiled against the vulnerable OpenEXR library, making it a privilege escalation vulnerability that can be leveraged to execute code with the permissions of the affected user.
The operational impact of CVE-2021-23169 extends across numerous industries that rely on OpenEXR for image processing, including film production, visual effects, and digital asset management systems. Applications such as Adobe After Effects, Blender, and various rendering engines that depend on OpenEXR for high dynamic range image handling become vulnerable to remote code execution attacks. This vulnerability aligns with ATT&CK technique T1059.007 for command and control through scripting, as attackers could potentially use the executed code to establish persistent access or escalate privileges. The flaw's exploitation potential is heightened in environments where users frequently process untrusted image files, such as online platforms, content management systems, or collaborative design tools that accept user-uploaded assets. Organizations using affected software versions face significant risk of unauthorized access, data compromise, and potential system takeover if exploited successfully.
Mitigation strategies for CVE-2021-23169 primarily focus on immediate version upgrading to OpenEXR 3.0.1 or later, which contains the necessary fixes for the heap-buffer overflow. System administrators should conduct comprehensive vulnerability assessments to identify all applications and services that depend on vulnerable OpenEXR versions, implementing patch management procedures to ensure timely deployment of security updates. Additional defensive measures include implementing strict input validation for image file processing, deploying sandboxing mechanisms for image handling operations, and configuring application whitelisting to restrict execution of untrusted image processing tasks. Network segmentation and monitoring solutions should be enhanced to detect potential exploitation attempts through anomalous image processing activities. Organizations should also consider implementing automated vulnerability scanning tools that can identify systems running vulnerable OpenEXR versions and generate alerts for immediate remediation. The fix addresses the root cause by implementing proper bounds checking and memory allocation validation within the copyIntoFrameBuffer function, preventing the overflow condition that previously allowed arbitrary code execution.