Executive Summary

This vulnerability is an arbitrary address write issue found in libaom, the reference AV1 codec implementation. It occurs because of a missing bounds check in the SVC (Scalable Video Coding) layer ID control function. An attacker can inject an arbitrary pointer into the cyclic refresh map field by supplying crafted image pixel values. The encoder then writes about 1,200 bytes to the attacker-controlled memory address. This behavior is deterministic and does not require any additional information leaks.

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Impact Analysis

If exploited, this vulnerability can lead to denial of service or potential code execution. An attacker who can supply frames to a network-facing libaom encoder with SVC enabled could cause the encoder to write to arbitrary memory locations, potentially hijacking control flow or crashing the application. This could affect applications such as real-time video conferencing or transcoding services that expose SVC encoder configuration to untrusted input.

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Detection Guidance

Detection of this vulnerability involves identifying if your system is running a vulnerable version of libaom, specifically versions prior to 3.14.0 where the missing bounds check in the SVC layer ID control function exists.

You can check the installed libaom version using commands like:

• On Linux, run: `pkg-config --modversion libaom` or check the package manager, e.g., `dpkg -l | grep libaom` or `rpm -q libaom`.
• If you have access to the application using libaom, verify if it uses SVC (Scalable Video Coding) features and if it accepts network input frames that could be crafted.

Currently, there are no specific network detection commands or signatures provided for this vulnerability, as it is triggered by crafted image pixel values supplied to the encoder.

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Mitigation Strategies

The primary mitigation step is to update libaom to version 3.14.0 or later, where the vulnerability has been fixed by adding proper bounds checks on spatial and temporal layer IDs in the SVC encoder.

If updating immediately is not possible, consider disabling the SVC (Scalable Video Coding) feature in libaom encoders to prevent exploitation via crafted frames.

Additionally, restrict or validate untrusted input frames supplied to the encoder, especially in network-facing applications such as real-time video conferencing or transcoding services.

Monitor for updates and patches from your software or OS vendor that include the fix.

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Compliance Impact

The vulnerability in libaom allows an attacker to perform arbitrary memory writes, potentially leading to denial of service or remote code execution in applications that use the AV1 codec with SVC enabled. This can impact the security and integrity of systems processing video data, especially in network-facing services.

While the CVE description and resources do not explicitly mention compliance with standards such as GDPR or HIPAA, exploitation of this vulnerability could lead to unauthorized control over systems handling sensitive data, thereby potentially violating requirements for data protection, system integrity, and availability mandated by these regulations.

Organizations using vulnerable versions of libaom in environments subject to such regulations should consider this vulnerability a significant risk to compliance, as successful exploitation could compromise confidentiality, integrity, or availability of protected data.

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