Conflicts between URL mapping and URL based access control., (Mon, Nov 24th)
Source SANS ISC Handlers Diary
Mentions 2 CVEs
Mentioned vulnerabilities
Description
We continue to encounter high-profile vulnerabilities related to the use of URL mapping (or "aliases") with URL-based access control. Last week, we wrote about the Oracle Identity Manager vulnerability. I noticed some scans for an older vulnerability with similar roots today:
Impact
For European organizations, this vulnerability poses a significant risk of unauthorized access and remote code execution on critical web applications, especially those using Java frameworks or Hitachi Vantara Pentaho Business Analytics Server. Exploitation can lead to data breaches, system compromise, lateral movement within networks, and disruption of business operations. Given the prevalence of web applications relying on URL rewriting and the complexity of access control in enterprise environments, many organizations could be exposed. The ability to bypass authentication and execute arbitrary code can undermine confidentiality, integrity, and availability of systems. This is particularly concerning for sectors with stringent data protection requirements such as finance, healthcare, and government. Additionally, the presence of automated scanning and exploitation attempts by botnets increases the likelihood of successful attacks if mitigations are not applied promptly.
Defensive guidance
1. Conduct a thorough audit of all URL rewriting and mapping rules in web server configurations (Apache, NGINX, etc.) to ensure they do not bypass authentication or access control unintentionally. 2. Review and test all URL-based access control policies to confirm they correctly enforce authentication and authorization on all endpoints, including those accessed via aliases or rewritten URLs. 3. Use precise and anchored regular expressions in access control rules to avoid unintended matches; avoid ambiguous patterns such as unescaped '.' characters. 4. Implement strict input validation and sanitization on all user-controllable inputs, especially those used in template rendering or command execution contexts, to prevent injection attacks. 5. Apply security patches and updates for affected products like Hitachi Vantara Pentaho Business Analytics Server promptly. 6. Employ runtime application self-protection (RASP) or web application firewalls (WAFs) configured to detect and block suspicious payloads targeting template injection or command execution. 7. Monitor logs and network traffic for scanning activity or exploitation attempts related to known vulnerable endpoints. 8. Educate developers and system administrators about the risks of URL mapping conflicts with access control and best practices for secure configuration.
Summary
The security threat centers on vulnerabilities caused by conflicts between URL mapping (aliases) and URL-based access control in web applications. URL mapping is commonly used to redirect or rewrite URLs to specific files or endpoints, such as mapping all API requests to a single index.html or serving default files when requested resources are missing. While these mappings facilitate usability and functionality, they can inadvertently bypass authentication controls if not properly aligned with access control policies. This is particularly problematic in Java-based applications, where complex routing and application-specific paths increase the risk of misconfiguration. A concrete example is the Hitachi Vantara Pentaho Business Analytics Server, which suffers from CVE-2022-43939 and CVE-2022-43769. In these cases, attackers exploit a template injection vulnerability in the ldapTreeNodeChildren endpoint by crafting URLs that include malicious payloads. The URL ends with a resource like /require.js, which is exempt from authentication due to URL mapping rules, but the backend still processes the request and executes injected code. This results in remote code execution without authentication. The root cause is often the failure to synchronize URL rewrite rules with access control logic, compounded by improper use of regular expressions that fail to anchor or correctly match URLs, allowing unauthorized access to sensitive endpoints. The threat is actively scanned for and exploited by botnets such as the "Chicago Rapper" Rondo. The broader implication is that any web application using URL mapping or aliases in conjunction with URL-based access control is at risk if these configurations are not carefully audited and tested.
References
Community reviews
Related threats
- CVE-2022-43769: Hitachi Vantara Pentaho Business Analytics (BA) Server · Hitachi Vantara Pentaho BA Server Special Element Injection VulnerabilityHighVulnerability
- CVE-2022-43939: Hitachi Vantara Pentaho Business Analytics (BA) Server · Hitachi Vantara Pentaho BA Server Authorization Bypass VulnerabilityHighVulnerability