Source: cve@mitre.org
httpdx 1.4.4 and earlier allows remote attackers to obtain the source code for a web page by appending a . (dot) character to the URI.
httpdx 1.4.4 and earlier is vulnerable to a critical flaw allowing remote attackers to disclose the source code of web pages. This vulnerability, triggered by appending a '.' (dot) to the URL, enables attackers to gain sensitive information, potentially leading to further exploitation and system compromise.
Step 1: Target Identification: Identify a web page hosted by an httpdx server, version 1.4.4 or earlier.
Step 2: Payload Construction: Construct a URL for the target web page, appending a '.' (dot) character to the end of the URI (e.g., http://target.com/index.html.).
Step 3: Request Submission: Send the crafted URL to the vulnerable httpdx server.
Step 4: Source Code Disclosure: The server, due to the vulnerability, will respond with the source code of the requested web page instead of rendering the page.
The vulnerability stems from inadequate input validation within httpdx's URI handling logic. The server fails to properly sanitize or filter the input, specifically the appended '.' character. This leads to a bypass of the intended file access restrictions. When a request is made with a URI ending in a dot, the server likely attempts to resolve the file path, but the dot character is not correctly handled, causing the server to return the source code instead of rendering the page. The root cause is a missing or insufficient check on the URI, allowing the attacker to bypass the intended security mechanisms. This is a form of path traversal vulnerability.
While no specific APTs are directly linked to this CVE, the nature of the vulnerability makes it attractive to various threat actors. The ability to obtain source code allows for the identification of other vulnerabilities. This vulnerability is not listed in the CISA KEV catalog, but its potential for information disclosure makes it a relevant threat.
Network traffic analysis: Examine HTTP requests for URIs ending in a dot ('.').
Web server logs: Analyze web server access logs for requests with suspicious URI patterns, specifically those ending in a dot.
File system monitoring: Monitor file access logs for unexpected access to web page source code files.
Intrusion Detection Systems (IDS): Configure IDS rules to detect requests with URIs ending in a dot.
Upgrade to httpdx version 1.4.5 or later, which includes a fix for this vulnerability.
Implement a Web Application Firewall (WAF) to filter out requests with suspicious URI patterns.
Review and harden web server configuration to restrict access to sensitive files and directories.
Regularly scan systems for known vulnerabilities using vulnerability scanners.
Implement input validation to sanitize all user-supplied data, including URIs.
Apply the principle of least privilege, restricting the permissions of the web server user.