Source: cve@mitre.org
BEA Systems WebLogic Express and WebLogic Server 5.1 SP1-SP6 allows remote attackers to bypass access controls for restricted JSP or servlet pages via a URL with multiple / (forward slash) characters before the restricted pages.
Remote attackers can bypass access controls in BEA Systems WebLogic Express and WebLogic Server, potentially gaining unauthorized access to restricted web resources like JSP or servlet pages. This vulnerability allows attackers to access sensitive information or execute malicious code, leading to data breaches and system compromise.
Step 1: Target Identification: The attacker identifies a WebLogic server running a vulnerable version and identifies restricted resources (e.g., JSP or servlet pages) that require authentication or authorization.
Step 2: Crafting the Malicious URL: The attacker constructs a URL targeting a restricted resource, but includes multiple forward slashes ('/') before the path to the resource. For example: http://target.example.com//protected/admin.jsp or http://target.example.com////protected/admin.jsp.
Step 3: URL Delivery: The attacker sends the crafted URL to the WebLogic server.
Step 4: Server Processing: The WebLogic server receives the request and attempts to process the URL.
Step 5: Access Control Bypass: Due to the flawed URL parsing, the server's access control mechanisms fail to correctly identify the restricted resource. The multiple slashes confuse the access control logic.
Step 6: Unauthorized Access: The server grants access to the restricted resource, bypassing the intended access control checks, allowing the attacker to view the content or execute the code within the JSP or servlet page.
The vulnerability stems from an improper handling of URL normalization within the WebLogic server. Specifically, the server's access control mechanisms fail to correctly parse URLs containing multiple forward slashes ('/'). The server's logic, designed to restrict access to protected resources, doesn't adequately sanitize or normalize the URL before checking access permissions. This allows an attacker to craft a URL with multiple slashes before the path to a restricted resource, bypassing the intended access control checks. The root cause is a flawed implementation of URL path matching, where the server's logic doesn't correctly interpret the multiple slashes, leading to a bypass of the access control filters. This is not a buffer overflow or race condition, but a logic flaw in the URL parsing and access control validation process.
While no specific APT groups are directly linked to this CVE, the ease of exploitation and potential impact make it a target for various threat actors. This vulnerability could be leveraged in conjunction with other exploits for a more comprehensive attack. This vulnerability is not listed in CISA KEV.
Analyze web server logs for requests containing multiple forward slashes ('/') in the URL path, especially those targeting sensitive resources.
Implement intrusion detection system (IDS) rules to flag requests with excessive forward slashes in the URL.
Monitor network traffic for suspicious HTTP requests targeting WebLogic servers.
Review web server configuration files for any misconfigurations related to URL handling or access control.
Upgrade to a patched version of WebLogic Server that addresses the vulnerability. Refer to the vendor's security advisories for specific patch versions.
Implement a Web Application Firewall (WAF) to filter malicious requests, including those with multiple forward slashes.
Review and harden access control configurations to ensure proper protection of sensitive resources.
Regularly scan the system for vulnerabilities using vulnerability scanners.
Implement URL normalization at the web server level to ensure that all URLs are properly sanitized before processing.