CVE-2019-10771 in iobroker.web
Summary
by MITRE
Characters in the GET url path are not properly escaped and can be reflected in the server response.
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Analysis
by VulDB Data Team • 11/26/2019
This vulnerability represents a classic reflected cross-site scripting issue that occurs when web applications fail to properly sanitize user input in URL parameters before incorporating them into server responses. The flaw manifests specifically within the GET request URL path where characters are not adequately escaped or filtered, allowing malicious payloads to be reflected back to users who visit the compromised URL. The vulnerability stems from improper input validation and output encoding practices within the web application's handling of HTTP requests, creating an attack surface where user-supplied data flows directly into response content without sufficient sanitization.
The technical implementation of this vulnerability typically involves web applications that construct response content by directly incorporating URL path components into HTML output or JavaScript contexts. When a malicious user crafts a URL containing specially crafted characters or script tags within the path parameters, these elements are not properly escaped during processing. This allows an attacker to inject malicious code that executes in the context of other users who access the vulnerable endpoint. The vulnerability can be exploited through various attack vectors including but not limited to HTML injection, JavaScript code execution, and session hijacking techniques. The impact extends beyond simple XSS as it can enable more sophisticated attacks such as credential theft, data exfiltration, and privilege escalation depending on the application's access controls and data sensitivity.
From an operational perspective this vulnerability presents significant risks to web application security and user privacy. The reflected nature of the attack means that exploitation requires user interaction with a maliciously crafted URL, typically through social engineering or phishing campaigns. However, the ease of exploitation and potential impact make this a high-value target for threat actors. The vulnerability aligns with CWE-79 which specifically addresses Cross-Site Scripting flaws in web applications, and maps to ATT&CK technique T1566 which covers spearphishing with a malicious link. Organizations may face compliance violations under regulations such as GDPR or PCI DSS when user data is compromised through such vulnerabilities. The attack surface is particularly concerning for applications handling sensitive user information or those that execute with elevated privileges.
Mitigation strategies for this vulnerability must address both the immediate security gap and implement comprehensive input validation controls. The primary defense involves implementing proper input sanitization and output encoding mechanisms that escape special characters in URL path components before incorporating them into response content. This includes applying context-aware encoding techniques such as HTML entity encoding for HTML contexts and JavaScript escaping for script contexts. Organizations should implement strict input validation that rejects or filters out potentially malicious characters and patterns from URL parameters. Additionally, deploying web application firewalls and implementing security headers such as Content Security Policy can provide additional layers of protection. Regular security testing including automated scanning and manual penetration testing should be conducted to identify and remediate similar vulnerabilities across the application portfolio. The implementation of proper error handling that does not expose internal application details also reduces information leakage that could aid attackers in exploiting this and related vulnerabilities.