CVE-2023-4863 Vulnerability: Analysis, Detection, Removal

What is CVE-2023-4863 Vulnerability?

CVE-2023-4863 is a critical remote code execution (RCE) vulnerability that affects certain implementations of WebP, an image format commonly used in web browsers. It exploits a heap buffer overflow condition due to improper input validation when handling crafted WebP images. This can enable attackers to execute arbitrary code on the target system, compromise its integrity, and potentially take complete control of affected devices. It has a CVSS score of 9.8, marking it as highly severe.

When was it discovered?

This vulnerability was disclosed publicly on September 21, 2023. Credit for discovery is attributed to a team of researchers from the Threat Analysis Group at Google. Following the initial discovery, patches for various platforms were rolled out quickly, reflecting the urgent attention this vulnerability received from software vendors.

Affected Products & Versions

A full list of affected software is still unknown at this time. Any software that uses the vulnerable library is likely affected. Due to the prolific use of libwebp as a software library, the attack surface of this vulnerability is likely extensive.

The patch to libwebp 1.3.2 fixes this issue upstream of its implementation. However, any software that ships with libwebp is potentially vulnerable. Software maintainers have also issued patches for their own products. Initial reconnaissance indicates that the following platforms have issues fixes for this vulnerability:

Common web browsers like Google Chrome, Mozilla Firefox, Mozilla Thunderbird, Brave, Tor, Opera, and Vivaldi.

Major operating systems like Debian, Ubuntu, Alpine, Gentoo, SUSE, Oracle, and Amazon have issues fixes for packaged software components.

Electron, Telegram, 1Password, and other desktop client applications.

Product	Versions Affected	Fixed Versions / Patch Links
Google Chrome	Versions before 116.0.5845.187	Patch Link
Mozilla Firefox	Versions before 117.0.1	Patch Link
Microsoft Edge	Versions before 116.0.1938.81	Patch Link

CVE-2023-4863 technical description

At its core, CVE-2023-4863 arises from a heap buffer overflow vulnerability in the libwebp library. When a specially crafted WebP image is processed, the overflow condition is triggered, allowing an attacker to write malicious code into memory spaces they shouldn't access. This condition grants attackers the ability to execute arbitrary code within the context of the vulnerable application. For example, sending a malicious WebP image to a user via email or embedding it in a website can lead to exploitation if the image is viewed in a vulnerable browser.

Tactics, Techniques & Procedures (TTPs)

Threat actors leveraging CVE-2023-4863 often use phishing emails with malicious WebP attachments or host-crafted images on compromised websites. Once viewed by a user with a vulnerable browser or application, the payload is executed, gaining control over the affected system.

Indicators of Compromise (IoCs)

Monitor for WebP images from untrusted sources and track malicious domains hosting such images. Logs may show suspicious downloads or traffic to/from known compromise domains. Additionally, scanned memory dump data might reveal artifacts of the crafted payload.

Known Proof-of-Concepts & Exploits

Proof-of-concept (PoC) exploits for CVE-2023-4863 have been widely circulated among security researchers. Active exploitation has already been observed in the wild, with attackers targeting end-user devices and enterprise networks. Exploit frameworks like Metasploit and other public repositories have showcased working examples.

How to detect CVE-2023-4863 vulnerability

Detection efforts can include monitoring network traffic for unusual requests involving crafted WebP files. On the host side, check application logs for abnormal behavior when processing image files. Use security tools like Huntress Managed EDR to detect and quarantine malicious payloads. SIEM rules can also be created to flag suspicious image-handling operations.

Impact & risk of CVE-2023-4863 vulnerability

The CVE-2023-4863 vulnerability can severely impact an organization’s data confidentiality, integrity, and availability. Exploitation may lead to data theft, system compromise, and even ransomware deployment. Browser exploits leveraging crafted images can also insert attackers into supply chain operations, with cascading effects across industries.

Mitigation & remediation strategies

To mitigate CVE-2023-4863, organizations should immediately apply vendor patches for all affected browsers and libraries. Additional steps include deploying access controls to reduce exposure to malicious image files, updating intrusion detection signatures, and isolating systems that handle high-risk media uploads. Disabling support for WebP where feasible can serve as a temporary workaround.

CVE-2023-4863 Vulnerability FAQs

CVE-2023-4863 is a heap buffer overflow vulnerability in the WebP image format library. Attackers can craft malicious WebP files to exploit this flaw, resulting in unauthorized code execution.

Typically, systems are compromised when users open malicious WebP images through vulnerable applications like browsers or email clients. Viewing these images triggers the exploit and executes the attacker’s payload.

While immediate patches reduce the risk, unpatched systems or legacy software may remain vulnerable. Active monitoring for IoCs and regular updates are critical to safeguarding against future threats.

Organizations can mitigate risks by applying all relevant patches, using threat detection tools, and educating employees about phishing tactics involving malicious files. Strong perimeter defenses and EDR solutions further enhance protection.