CVE-2001-1266 in DNHTTPD
Summary
by MITRE
Directory traversal vulnerability in Doug Neal s HTTPD Daemon (DNHTTPD) before 0.4.1 allows remote attackers to view arbitrary files via a .. (dot dot) attack using the dot hex code %2E .
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Analysis
by VulDB Data Team • 05/31/2018
The vulnerability identified as CVE-2001-1266 represents a critical directory traversal flaw within the Doug Neal HTTPD Daemon (DNHTTPD) software version 0.4.0 and earlier. This security weakness allows remote attackers to access arbitrary files on the affected system by exploiting improper input validation mechanisms. The vulnerability specifically manifests when the web server fails to adequately sanitize user-supplied input containing directory traversal sequences, enabling malicious actors to navigate beyond the intended document root directory and access restricted system files.
The technical implementation of this vulnerability stems from the daemon's insufficient validation of the dot hex code %2E within file path requests. When a remote attacker submits a request containing this encoded sequence, the HTTPD daemon processes it without proper sanitization, allowing the traversal mechanism to function as intended. This flaw directly maps to CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks. The vulnerability exploits the fundamental principle that web servers should restrict file access to predefined directories and prevent users from accessing system resources outside of the designated web root.
The operational impact of this vulnerability extends beyond simple information disclosure, as it provides attackers with the capability to access sensitive system files including configuration data, user credentials, and potentially system binaries. An attacker could leverage this vulnerability to retrieve critical files such as password hashes, database connection strings, or application configuration details that could facilitate further exploitation. The remote nature of this attack means that no local system access is required, making it particularly dangerous as it can be exploited from any network location. This vulnerability aligns with ATT&CK technique T1083 (File and Directory Discovery) and T1566 (Phishing) as attackers may use the retrieved information to craft more sophisticated social engineering campaigns or to identify additional system vulnerabilities.
Mitigation strategies for CVE-2001-1266 require immediate implementation of software updates to version 0.4.1 or later, which contain the necessary fixes to address the directory traversal vulnerability. Organizations should also implement input validation measures that explicitly filter or reject encoded directory traversal sequences such as %2E, %2F, and similar hex encodings that could be used to manipulate file paths. Network administrators should consider implementing web application firewalls that can detect and block suspicious path traversal attempts, while system administrators should conduct comprehensive audits of all web server configurations to ensure that no other applications suffer from similar vulnerabilities. Additionally, implementing proper access controls and privilege separation can limit the damage that could result from successful exploitation, ensuring that even if an attacker gains access to the web server, they cannot escalate privileges or access critical system resources beyond the intended web root directory.