CVE-2001-0131 in HTTP Server
Summary
by MITRE
htpasswd and htdigest in Apache 2.0a9, 1.3.14, and others allows local users to overwrite arbitrary files via a symlink attack.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 05/19/2019
The vulnerability identified as CVE-2001-0131 represents a critical security flaw in Apache HTTP Server versions 2.0a9, 1.3.14, and other affected releases. This issue specifically impacts the htpasswd and htdigest utilities that are commonly used for managing authentication credentials in web server environments. The vulnerability stems from improper handling of symbolic links during file creation operations, creating a significant attack surface for local users who can exploit this weakness to overwrite arbitrary files on the system.
The technical flaw manifests when these utilities create temporary files during the process of updating authentication files. The implementation fails to properly validate or handle symbolic link references, allowing a local attacker to manipulate the file creation process by pre-creating symbolic links in strategic locations. When the utility attempts to write to what it believes is a legitimate file path, it actually overwrites the target of the symbolic link rather than the intended file, potentially allowing an attacker to modify critical system files or inject malicious content into authentication databases. This type of vulnerability is categorized under CWE-59 as improper link resolution, which directly relates to the insecure handling of symbolic links in file operations.
The operational impact of this vulnerability is substantial as it provides local users with the ability to escalate privileges and compromise system integrity. An attacker could potentially overwrite system configuration files, authentication databases, or even critical executables through this mechanism. The attack requires local system access but does not need network connectivity, making it particularly dangerous in environments where local privilege escalation is a concern. This vulnerability undermines the security of Apache installations by potentially allowing unauthorized modification of authentication mechanisms that are fundamental to web server security.
Mitigation strategies for this vulnerability involve immediate patching of affected Apache installations to versions that properly handle symbolic links during file operations. System administrators should ensure that all instances of htpasswd and htdigest utilities are updated to secure versions that implement proper file path validation and symbolic link resolution checks. Additionally, organizations should conduct comprehensive audits of their Apache installations to identify all affected versions and implement proper file permissions and access controls. The ATT&CK framework categorizes this as a privilege escalation technique through file system manipulation, emphasizing the need for proper file system security controls and regular security updates to prevent exploitation of such weaknesses in web server software components.