CVE-2008-1270 in lighttpd
Summary
by MITRE
mod_userdir in lighttpd 1.4.18 and earlier, when userdir.path is not set, uses a default of $HOME, which might allow remote attackers to read arbitrary files, as demonstrated by accessing the ~nobody directory.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 12/31/2024
The vulnerability identified as CVE-2008-1270 affects lighttpd web servers running version 1.4.18 or earlier, specifically when the userdir.path configuration directive is not explicitly set. This represents a critical security flaw that stems from improper default configuration handling within the mod_userdir module. When administrators fail to explicitly define the userdir.path parameter, the module defaults to using the $HOME environment variable, creating an exploitable condition that can be leveraged by remote attackers to gain unauthorized access to sensitive files across the system.
The technical flaw manifests through the improper handling of user directory paths in lighttpd's mod_userdir module. When userdir.path is unset, the system defaults to using the $HOME variable, which typically resolves to the home directory of the user account running the lighttpd process. This default behavior creates a path traversal vulnerability because the module does not properly validate or sanitize the user directory paths before resolving them. Attackers can exploit this by crafting malicious URLs that reference user directories, particularly targeting system accounts like 'nobody' or other low-privilege users whose home directories might contain sensitive information.
The operational impact of this vulnerability is significant as it allows remote attackers to bypass normal access controls and read arbitrary files on the server. The demonstration case involving access to the ~nobody directory illustrates how attackers can traverse user directories and potentially access system configuration files, log files, or other sensitive data that might be stored in these locations. This vulnerability essentially provides a backdoor mechanism for information disclosure attacks, enabling adversaries to gather intelligence about the system and potentially identify other vulnerabilities or attack vectors.
The flaw aligns with CWE-22, which describes improper limitation of a pathname to a restricted directory, and represents a classic case of insecure default configurations. From an ATT&CK perspective, this vulnerability maps to T1083 (File and Directory Discovery) and T1005 (Data from Local System) as attackers can use this weakness to enumerate and extract sensitive files from the compromised system. The vulnerability also reflects poor input validation practices and inadequate access control mechanisms within the web server's user directory handling functionality.
Administrative mitigations for this vulnerability include explicitly setting the userdir.path configuration directive to a restricted directory that does not grant access to sensitive system files. System administrators should ensure that the userdir.path is configured to point to a dedicated, secure directory that does not expose system resources. Additionally, disabling the mod_userdir module entirely when user directory functionality is not required provides a more secure approach. Regular security audits should verify that all web server configurations properly define user directory paths and that default configurations are not being used in production environments. The vulnerability underscores the critical importance of proper configuration management and the dangers of relying on insecure default settings in web server software.