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CVE Spotlight: Understanding CVE 2023-4863 Libwebp Heap Overflow
4/1/2024 - Brian O'Neill

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Just a few months ago, in September 2023, a critical (high-severity) heap overflow vulnerability was discovered in certain versions of Libwebp – a popular image codec library used in a variety of common applications, including web browsers like Google Chrome and Microsoft Edge.

Troublingly, in the analysis of CVE 2023-4863, it was found that threat actors could exploit this particular heap overflow vulnerability without requiring any interaction from a user.

Using a specially crafted malicious WebP file (and without authoring malware), a threat actor could force the decoding algorithm used in vulnerable versions of the Libwebp library to write data outside the scope of its usual memory allocation process. If an instance of software using a vulnerable Libwebp version were to process the malicious WebP file, it could lead to a Remote Code Execution or Denial of Service attack.

Thankfully, shortly after this alarming vulnerability was identified, a new version of Libwebp was released to patch it. As ever, successfully avoiding attacks that exploit heap overflow flaws like CVE 2023-4863 often boils down to religiously checking for relevant software updates and applying them as soon as they're available.

Learning from CVE 2023-4863

The sudden discovery of obviously severe vulnerabilities like CVE 2023-4863 highlights an unfortunate truth in modern cybersecurity: motivated threat actors will tirelessly attempt to identify new, unseen vulnerabilities in the software libraries we passively trust, and threat researchers may not be able to discover and publish information about these vulnerabilities before devastating attacks occur.

The incentive to find and exploit vulnerabilities like CVE 2023-4863 is strong, after all. For most threat actors, exploiting unknown heap overflow vulnerabilities with specially crafted payloads is far simpler than authoring malware capable of bypassing the increasingly robust, sophisticated antivirus technologies potential victims can purchase on the modern cybersecurity market.

Specially crafted files intended to exploit heap overflow vulnerabilities like the CVE-2023-4863 example will, in all likelihood, bypass the antivirus technologies our applications rely on to ward off malicious file content, and the results of such a breach can be just as devastating as any virus or malware attack.

Cloudmersive Content Verification

Thankfully, one way we can mitigate attacks using specially crafted files to exploit heap overflow vulnerabilities is by incorporating content verification policies in our virus and malware file scans. In doing so, we can ensure files conform to rigid file formatting standards without needing to stay on top of image processing exploits quite as regularly.

The Cloudmersive Advanced Virus Scan API combines in-depth content verification policies with powerful virus and malware detection capabilities to identify specially crafted file threats.

For more information on Cloudmersive Advanced Virus Scan API content verification capabilities, please do not hesitate to reach out to a member of our team.

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