CVE-2015-1419 in vsftpd
Summary
by MITRE
Unspecified vulnerability in vsftp 3.0.2 and earlier allows remote attackers to bypass access restrictions via unknown vectors, related to deny_file parsing.
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Analysis
by VulDB Data Team • 11/30/2024
The vulnerability identified as CVE-2015-1419 represents a critical access control flaw within the vsftpd FTP server software version 3.0.2 and earlier. This issue resides in the deny_file parsing mechanism, which is responsible for controlling file access restrictions within the FTP server environment. The unspecified nature of the vulnerability vectors suggests that attackers can exploit multiple pathways to circumvent the intended access controls, making the flaw particularly dangerous as it may not be immediately apparent or easily detectable through standard security scanning methods. The vulnerability specifically targets the configuration parsing logic that determines which files or directories should be restricted from access, potentially allowing unauthorized users to gain access to resources they should not be permitted to reach.
The technical implementation of this vulnerability stems from weaknesses in how vsftpd processes the deny_file directive within its configuration files. When administrators configure access restrictions using deny_file directives, the server should properly parse these settings to enforce the intended access controls. However, the flaw in vsftpd 3.0.2 and earlier versions allows attackers to manipulate the parsing process in such a way that the access restrictions become ineffective. This parsing failure could occur through various means including malformed input, improper handling of special characters, or incorrect interpretation of configuration parameters that should normally prevent access to certain files or directories. The vulnerability essentially creates a bypass mechanism that allows attackers to access restricted resources regardless of the configured access control settings.
From an operational perspective, this vulnerability presents a severe risk to organizations relying on vsftpd for their file transfer services. Attackers who successfully exploit this flaw could gain unauthorized access to sensitive files, directories, or system resources that should be protected by the FTP server's access controls. The impact extends beyond simple file access, as this vulnerability could potentially enable attackers to escalate privileges, exfiltrate confidential data, or use the compromised FTP server as a foothold for further attacks within the network infrastructure. The fact that this vulnerability affects versions up to 3.0.2 means that organizations running older deployments of vsftpd are particularly at risk, as these versions have been widely deployed across various enterprise environments. The vulnerability's potential for remote exploitation makes it especially dangerous as attackers do not require local access to the system to exploit the flaw.
Security professionals should immediately implement mitigation strategies including upgrading to vsftpd version 3.0.3 or later, which contains the necessary patches to address this vulnerability. Organizations should also conduct thorough audits of their FTP server configurations to ensure that deny_file directives are properly implemented and validated. Network segmentation and additional access controls should be implemented to minimize the potential impact of any successful exploitation attempts. The vulnerability aligns with CWE-284, which covers improper access control issues, and represents a classic example of how configuration parsing flaws can create security bypass mechanisms. From an ATT&CK framework perspective, this vulnerability could be categorized under privilege escalation and defense evasion techniques, as it allows attackers to bypass security controls and maintain access to restricted resources. Regular security assessments and monitoring of FTP server configurations should be implemented to detect any potential exploitation attempts and ensure that access control mechanisms remain effective against known vulnerabilities.