CVE-2014-8479 in Scalance X-408
Summary
by MITRE
The FTP server on Siemens SCALANCE X-300 switches with firmware before 4.0 and SCALANCE X 408 switches with firmware before 4.0 allows remote authenticated users to cause a denial of service (reboot) via crafted FTP packets.
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Analysis
by VulDB Data Team • 04/11/2022
The vulnerability identified as CVE-2014-8479 affects Siemens SCALANCE X-300 and SCALANCE X 408 industrial network switches operating with firmware versions prior to 4.0. These devices are part of Siemens' industrial automation and control systems portfolio, designed for harsh industrial environments where network reliability is critical. The affected switches incorporate FTP server functionality as part of their network management capabilities, enabling remote administration and firmware updates through standard file transfer protocols. This vulnerability represents a significant security concern for industrial control systems where availability of network infrastructure directly impacts operational continuity and safety.
The technical flaw resides in the FTP server implementation within these industrial switches, specifically in how they process incoming FTP packets from authenticated users. When remote authenticated users send crafted FTP packets to the vulnerable devices, the system fails to properly validate or handle these malformed inputs, leading to unexpected behavior that ultimately results in system reboot. This represents a classic buffer overflow or input validation vulnerability where the FTP server does not adequately sanitize user-provided data before processing. The vulnerability can be classified under CWE-121 as a buffer copy without size check, or CWE-122 as a buffer copy with insufficient space, though the specific implementation details suggest a more fundamental protocol handling flaw that causes the system to crash rather than execute arbitrary code.
The operational impact of this vulnerability extends beyond simple denial of service, particularly in industrial environments where network availability is paramount. A successful exploitation of CVE-2014-8479 can cause unexpected system reboots of industrial switches, potentially disrupting critical network communications between control systems and field devices. In SCADA environments, such disruptions can lead to loss of visibility into process control, potential safety hazards, and operational downtime that may require manual intervention to restore network connectivity. The vulnerability affects both SCALANCE X-300 and SCALANCE X 408 models, which are commonly deployed in critical infrastructure sectors including power generation, water treatment, and manufacturing facilities where network reliability directly impacts operational safety and productivity.
From a threat modeling perspective, this vulnerability aligns with ATT&CK technique T1499.004 which covers network denial of service attacks, and represents a privilege escalation scenario where authenticated users can leverage their access to cause system-wide disruptions. The attack vector requires only authenticated access to the FTP service, making it particularly concerning in environments where FTP credentials might be compromised or where default credentials are not properly changed. Organizations should consider implementing network segmentation to limit access to these industrial switches, requiring strong authentication mechanisms, and deploying monitoring solutions to detect unusual reboot patterns that might indicate exploitation attempts. The vulnerability also highlights the importance of keeping industrial network equipment updated with security patches, as the issue was resolved in firmware version 4.0 and subsequent releases.
Mitigation strategies should include immediate firmware updates to version 4.0 or later for all affected SCALANCE switches, along with proper network access controls to limit FTP service exposure. Network administrators should implement access control lists to restrict FTP service access to trusted management stations only, and consider disabling FTP services entirely if they are not required for operational purposes. The vulnerability demonstrates the critical need for industrial cybersecurity practices that include regular vulnerability assessments, proper patch management procedures, and continuous monitoring of industrial network infrastructure to detect potential exploitation attempts. Organizations should also consider implementing network intrusion detection systems specifically tuned to detect anomalous FTP traffic patterns that might indicate exploitation attempts against industrial control systems.