Source: cve@mitre.org
Incomplete blacklist in sanitize_string in Zenphoto before 1.4.9 allows remote attackers to conduct cross-site scripting (XSS) attacks.
Zenphoto versions prior to 1.4.9 are vulnerable to Cross-Site Scripting (XSS) attacks due to an incomplete blacklist in the sanitize_string function. This allows attackers to inject malicious JavaScript code into web pages, potentially leading to account compromise, data theft, or website defacement. Successful exploitation requires user interaction to view the crafted content.
Step 1: Payload Injection: An attacker crafts a malicious payload containing JavaScript code designed to execute in the victim's browser. This payload is typically embedded within HTML tags or attributes.
Step 2: Input Submission: The attacker submits the crafted payload through a vulnerable input field within Zenphoto, such as a comment, title, or description.
Step 3: Data Storage: The Zenphoto application stores the attacker's input, including the malicious payload, in its database or other storage mechanisms.
Step 4: Content Rendering: When a victim views the content containing the attacker's input (e.g., a blog post, image description), the Zenphoto application retrieves the stored data and renders it in the victim's browser.
Step 5: XSS Execution: The victim's browser interprets the malicious JavaScript payload as part of the website's content, executing the attacker's code. This allows the attacker to perform actions on behalf of the victim, such as stealing cookies, redirecting the user, or defacing the website.
The vulnerability stems from an inadequate blacklist implementation within the sanitize_string function of Zenphoto. This function is responsible for filtering user-supplied input to prevent malicious code injection. The incomplete blacklist fails to effectively neutralize all possible XSS vectors. Attackers can bypass the filter by crafting payloads that utilize alternative character encodings, obfuscation techniques, or exploiting overlooked HTML tags and attributes. The root cause is a logic error in the filtering logic, allowing certain malicious payloads to pass through undetected. The specific flaw lies in the insufficient coverage of the blacklist, failing to account for all potential XSS attack vectors. The lack of a robust input validation strategy exacerbates the issue.
While no specific APT groups are directly linked to this CVE, XSS vulnerabilities are commonly exploited by various threat actors, including those involved in credential harvesting, malware distribution, and website defacement. This vulnerability could be leveraged by opportunistic attackers. CISA KEV status: Not Listed
Web Application Firewall (WAF) Logs: Examine WAF logs for suspicious HTTP requests containing common XSS payloads (e.g., <script>, onerror, javascript:).
Server-Side Logs: Analyze server logs (e.g., access.log, error.log) for unusual patterns, such as repeated attempts to inject HTML tags or JavaScript code into input fields.
Network Traffic Analysis: Monitor network traffic for unusual HTTP requests, especially those containing JavaScript code or suspicious character sequences.
Content Security Policy (CSP) Violations: If CSP is enabled, monitor for CSP violation reports, which can indicate XSS attempts.
Vulnerability Scanners: Employ vulnerability scanners to identify the presence of this and other XSS vulnerabilities.
Upgrade Zenphoto: Update to Zenphoto version 1.4.9 or later, which includes a fix for this vulnerability.
Implement Input Validation: Implement robust input validation to sanitize all user-supplied data, ensuring that only expected characters and formats are allowed. This should include whitelisting acceptable characters rather than relying solely on blacklists.
Output Encoding: Implement output encoding to escape potentially dangerous characters (e.g., <, >, &, ", ') before displaying user-supplied data in HTML, JavaScript, or other contexts.
Content Security Policy (CSP): Implement a strong CSP to restrict the sources from which the browser can load resources, mitigating the impact of XSS attacks.
Web Application Firewall (WAF): Deploy a WAF to filter malicious traffic and block known XSS payloads.
Regular Security Audits: Conduct regular security audits and penetration testing to identify and address vulnerabilities.