Source: cve@mitre.org
Cross-site scripting (XSS) vulnerability in the Troubleshooting Reporting System feature in AgileBits 1Password 3.9.9 might allow remote attackers to inject arbitrary web script or HTML via a crafted User-Agent HTTP header that is not properly handled in a View Troubleshooting Report action.
1Password 3.9.9 is vulnerable to a cross-site scripting (XSS) attack, allowing attackers to inject malicious HTML or JavaScript into the application via a crafted User-Agent HTTP header. This vulnerability could lead to session hijacking, data theft, or website defacement by exploiting the application's troubleshooting reporting feature.
Step 1: Payload Delivery: The attacker crafts a malicious User-Agent string containing HTML or JavaScript code. This payload is designed to execute within the context of a user's browser when the troubleshooting report is viewed.
Step 2: Request Submission: The attacker sends an HTTP request to the vulnerable 1Password application, including the crafted User-Agent string in the HTTP header.
Step 3: Data Storage: The application stores the malicious User-Agent string, likely in a log file or database associated with the Troubleshooting Reporting System.
Step 4: Report Generation: A legitimate user, or the attacker, triggers the generation of a troubleshooting report. This might involve navigating to a specific page or performing an action that causes the report to be generated.
Step 5: Code Execution: The application retrieves the stored User-Agent string and displays it within the troubleshooting report. Because the User-Agent string is not properly sanitized, the injected HTML or JavaScript code is executed by the user's browser.
The vulnerability stems from a failure to properly sanitize the User-Agent HTTP header before displaying it within the Troubleshooting Reporting System. Specifically, the application directly renders the contents of the User-Agent header without escaping special characters or filtering potentially malicious HTML or JavaScript. This allows an attacker to inject arbitrary code that will be executed in the context of a legitimate user's session when they view the troubleshooting report. The root cause is a lack of input validation and output encoding (specifically, HTML encoding) of the User-Agent header when generating the troubleshooting report.
Due to the age of the vulnerability, specific APT groups are unlikely to be actively targeting this. However, it could be incorporated into broader attack campaigns. Not listed on CISA KEV due to its age and specific version.
Monitor HTTP request logs for unusual User-Agent strings containing HTML tags or JavaScript code (e.g., <script>, <iframe>, onload).
Analyze web server logs for requests to the vulnerable application with suspicious User-Agent headers.
Implement a Web Application Firewall (WAF) with rules to detect and block XSS payloads in HTTP headers.
Monitor network traffic for unusual activity originating from the 1Password application, such as attempts to access external domains or execute JavaScript.
Examine the application's source code (if available) for instances where the User-Agent header is used without proper sanitization.
Upgrade to a patched version of 1Password that addresses the XSS vulnerability. This is the primary and most effective remediation.
Implement input validation to sanitize the User-Agent header, removing or encoding potentially malicious characters (e.g., <, >, ", ').
Implement output encoding (HTML encoding) to ensure that any user-supplied data, including the User-Agent header, is properly escaped before being displayed in the troubleshooting report.
Use a Content Security Policy (CSP) to restrict the execution of JavaScript from untrusted sources.
Regularly scan the application for vulnerabilities using static and dynamic analysis tools.
Review and update the application's security configuration to minimize the attack surface.