CVE-2022-23638 in svg-sanitizer
Summary
by MITRE • 02/15/2022
svg-sanitizer is a SVG/XML sanitizer written in PHP. A cross-site scripting vulnerability impacts all users of the `svg-sanitizer` library prior to version 0.15.0. This issue is fixed in version 0.15.0. There is currently no workaround available.
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Analysis
by VulDB Data Team • 02/17/2022
The CVE-2022-23638 vulnerability affects the svg-sanitizer PHP library, which serves as a critical security component for sanitizing SVG and XML content in web applications. This library is widely utilized across various PHP-based systems to prevent malicious SVG content from being processed, thereby protecting against potential security threats that could arise from untrusted SVG inputs. The vulnerability specifically targets users of versions prior to 0.15.0, making it a significant concern for organizations that have not yet upgraded their implementations. The flaw represents a serious degradation in the library's ability to properly sanitize potentially malicious content, creating a pathway for attackers to exploit the system through cross-site scripting attacks that bypass the intended security measures.
The technical nature of this vulnerability stems from inadequate input validation and sanitization mechanisms within the svg-sanitizer library. When processing SVG content, the library fails to properly handle certain edge cases or malformed elements that could contain malicious script code. This weakness allows attackers to craft SVG files containing embedded JavaScript or other malicious payloads that are not properly neutralized during the sanitization process. The vulnerability operates at the core of the library's parsing and sanitization logic, where it should be removing or escaping dangerous elements but instead permits them to pass through undetected. This represents a classic cross-site scripting flaw that can be exploited when the sanitized content is subsequently rendered in web browsers, allowing malicious code execution in the context of the victim's session.
The operational impact of CVE-2022-23638 extends beyond simple data exposure, as it enables attackers to execute arbitrary code within user browsers when sanitized SVG content is displayed. This vulnerability can be exploited through various attack vectors including file uploads, content management systems, or any application that accepts SVG input from untrusted sources. The consequences include potential session hijacking, credential theft, redirection to malicious sites, and execution of malicious scripts that could compromise user browsers and potentially the underlying system. Organizations using vulnerable versions of the library face significant risk of successful exploitation, particularly in environments where SVG content is frequently processed or uploaded by users. The lack of a workaround means that organizations must immediately upgrade to version 0.15.0 or higher to mitigate the risk, as no temporary fixes are available to address the underlying sanitization issues.
This vulnerability aligns with CWE-79, which describes cross-site scripting flaws in software, and represents a failure in proper input sanitization that allows malicious content to persist in the system. From an ATT&CK framework perspective, this vulnerability maps to T1566.001 (Phishing via Social Media) and T1059.007 (Command and Scripting Interpreter: JavaScript) as attackers can leverage the XSS capability to execute malicious JavaScript in user browsers. The impact is particularly severe because SVG files are commonly used in web applications, making this vulnerability exploitable across numerous attack surfaces. Security teams should prioritize immediate remediation efforts, including thorough vulnerability assessments of systems using this library, monitoring for potential exploitation attempts, and implementing additional defensive measures such as content security policies to limit the impact if exploitation occurs. The vulnerability underscores the critical importance of keeping security libraries updated and demonstrates how seemingly minor flaws in sanitization components can create substantial security risks for entire applications.