CVE-2021-29109 in Portal for ArcGIS
Summary
by MITRE • 10/02/2021
A reflected XSS vulnerability in Esri Portal for ArcGIS version 10.9 and below may allow a remote attacker able to convince a user to click on a crafted link which could potentially execute arbitrary JavaScript code in the user’s browser.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 10/08/2021
The reflected cross-site scripting vulnerability identified as CVE-2021-29109 resides within Esri Portal for ArcGIS version 10.9 and earlier installations, representing a critical security weakness that compromises user browser integrity. This vulnerability falls under the Common Weakness Enumeration category CWE-79 which specifically addresses cross-site scripting flaws where untrusted data is directly incorporated into web pages without proper validation or sanitization. The affected system processes user input through URL parameters or other web interface elements, creating an environment where malicious payloads can be injected and executed within the context of a victim's browser session.
The technical exploitation of this vulnerability occurs when an attacker crafts a malicious URL containing JavaScript code within the application's input parameters. When a victim clicks on this crafted link, the malicious script is reflected back to the user's browser through the web application's response without proper output encoding or validation. This reflection mechanism allows the attacker to execute arbitrary JavaScript code within the victim's browser context, potentially enabling session hijacking, credential theft, or redirection to malicious sites. The vulnerability specifically targets the portal's handling of user-supplied data that is returned in HTTP responses without adequate sanitization measures.
The operational impact of this reflected XSS vulnerability extends beyond simple script execution, as it can enable sophisticated attack chains that compromise the entire user session and potentially escalate to more severe security incidents. Attackers can leverage this vulnerability to steal user authentication tokens, modify web application behavior, or redirect users to phishing sites that appear legitimate. The attack vector requires social engineering to convince users to click malicious links, but once executed, the consequences can be severe as the attacker gains the ability to operate within the victim's authenticated session. This vulnerability particularly affects organizations relying on Esri Portal for ArcGIS for mapping and spatial data management, where users may have elevated privileges and access to sensitive geospatial information.
Mitigation strategies for CVE-2021-29109 should prioritize immediate remediation through official patches provided by Esri, as the vendor has released updates addressing this specific vulnerability. Organizations should implement comprehensive input validation and output encoding mechanisms to prevent malicious data from being reflected back to users. The implementation of Content Security Policy headers can provide additional defense-in-depth measures by restricting script execution and limiting the attack surface available to potential attackers. Regular security assessments and web application firewalls should be deployed to monitor and block suspicious traffic patterns. Network segmentation and user access controls can help limit the potential impact if exploitation occurs, while security awareness training can reduce the risk of successful social engineering attacks that rely on user interaction with malicious links. The vulnerability demonstrates the critical importance of maintaining up-to-date software versions and implementing proper security controls as outlined in the ATT&CK framework's web application attack patterns.