CVE-2005-1238 in iSeries AS400
Summary
by MITRE
By design, the built-in FTP server for iSeries AS/400 systems does not support a restricted document root, which allows attackers to read or write arbitrary files, including sensitive QSYS databases, via a full pathname in a GET or PUT request.
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Analysis
by VulDB Data Team • 07/24/2017
The vulnerability described in CVE-2005-1238 represents a critical access control flaw within the iSeries AS/400 system's built-in FTP server implementation. This issue stems from the fundamental design decision to omit restricted document root functionality, creating a pathway for unauthorized file system access that extends far beyond typical FTP server security boundaries. The iSeries AS/400 platform, developed by IBM, operates within enterprise environments where data sensitivity and system integrity are paramount, making this vulnerability particularly dangerous in production settings.
The technical flaw manifests through the FTP server's inability to enforce directory restrictions on file operations, allowing attackers to bypass normal access controls by specifying full pathnames in GET or PUT requests. This design oversight enables malicious actors to navigate the entire file system hierarchy without proper authentication or authorization, potentially accessing sensitive system files, configuration data, and database contents. The vulnerability specifically affects the QSYS database system, which contains critical system information, user credentials, and operational data that forms the foundation of AS/400 system functionality. This unrestricted access capability directly violates the principle of least privilege and creates opportunities for both information disclosure and system compromise.
The operational impact of this vulnerability extends beyond simple file access, as it provides attackers with the capability to modify or delete critical system files, potentially leading to system instability, data corruption, or complete system compromise. The ability to read QSYS databases means that attackers can access sensitive information including system configuration parameters, user authentication data, and business-critical database contents. This vulnerability enables a range of malicious activities from passive information gathering to active system manipulation, making it particularly attractive to threat actors targeting enterprise environments. The lack of proper path validation and access control enforcement creates an attack surface that can be exploited without requiring elevated privileges or specialized knowledge of system internals.
From a cybersecurity perspective, this vulnerability aligns with CWE-22 (Improper Limiting of a Pathname to a Restricted Directory) and represents a classic example of inadequate input validation and access control implementation. The flaw demonstrates how design decisions can create fundamental security weaknesses that persist across system lifecycles without proper mitigation. Organizations running iSeries AS/400 systems are particularly vulnerable due to the critical nature of these platforms in enterprise environments, where they often host sensitive business data and critical operational systems. The vulnerability also maps to ATT&CK technique T1078 (Valid Accounts) and T1566 (Phishing) as attackers can leverage this flaw to establish persistent access and move laterally within compromised systems. Mitigation efforts should include implementing network segmentation, deploying firewall rules to restrict FTP access, applying system patches when available, and implementing monitoring solutions to detect unauthorized file access patterns. Organizations must also consider the broader security implications of legacy system components and ensure proper access controls are implemented through configuration management and regular security assessments.