CVE-2016-8352 in ConneXium
Summary
by MITRE
An issue was discovered in Schneider Electric ConneXium firewalls TCSEFEC23F3F20 all versions, TCSEFEC23F3F21 all versions, TCSEFEC23FCF20 all versions, TCSEFEC23FCF21 all versions, and TCSEFEC2CF3F20 all versions. A stack-based buffer overflow can be triggered during the SNMP login authentication process that may allow an attacker to remotely execute code.
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Analysis
by VulDB Data Team • 09/01/2020
The CVE-2016-8352 vulnerability represents a critical stack-based buffer overflow flaw in Schneider Electric ConneXium firewalls, specifically affecting multiple hardware models including TCSEFEC23F3F20, TCSEFEC23F3F21, TCSEFEC23FCF20, TCSEFEC23FCF21, and TCSEFEC2CF3F20 across all their respective software versions. This vulnerability resides within the SNMP login authentication process, making it particularly dangerous as SNMP is commonly used for network management and monitoring operations. The flaw stems from inadequate input validation during authentication procedures where the firewall fails to properly bounds-check user-supplied data before copying it into fixed-size memory buffers. This oversight creates a condition where maliciously crafted SNMP login requests can overflow the allocated stack space, potentially corrupting adjacent memory locations and overwriting critical program execution data. The vulnerability's exploitation potential is heightened by its remote accessibility, eliminating the need for physical access or network proximity to the affected devices.
The technical implementation of this buffer overflow vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent stack memory. The flaw specifically manifests during SNMP authentication when the firewall processes incoming login credentials, particularly username and password parameters. Attackers can craft specially formatted SNMP packets that contain overly long strings, causing the authentication function to write beyond the intended buffer boundaries. This memory corruption can potentially overwrite return addresses, function pointers, or other critical execution context data, enabling remote code execution. The vulnerability's impact extends beyond simple privilege escalation as it provides attackers with complete control over the affected firewall's operational functions, including access to network traffic filtering, routing decisions, and management interfaces. Network administrators may find their security posture severely compromised as the firewall becomes a potential entry point for broader network infiltration.
From an operational perspective, this vulnerability poses significant risks to industrial control systems and network security infrastructures that rely on Schneider Electric firewalls for perimeter protection. The remote code execution capability allows attackers to establish persistent access, modify firewall rules, redirect network traffic, or even use the compromised device as a pivot point for attacking internal network segments. The vulnerability's presence in multiple firmware versions indicates a systemic design flaw that affects a substantial portion of Schneider Electric's ConneXium firewall product line, potentially impacting critical infrastructure across various sectors including energy, manufacturing, and transportation. Security professionals must consider that attackers may leverage this vulnerability to gain unauthorized access to sensitive network environments, particularly in scenarios where these firewalls are deployed in critical infrastructure networks. The lack of local authentication requirements for exploitation means that attackers can target these devices from anywhere on the internet, making the vulnerability particularly concerning for organizations with limited network segmentation or monitoring capabilities. Organizations may experience service disruption, data breaches, or unauthorized network access that could compromise operational technology environments.
Mitigation strategies for CVE-2016-8352 should prioritize immediate firmware updates from Schneider Electric, as the vendor likely released patches addressing the buffer overflow conditions. Network segmentation should be implemented to isolate affected firewalls from critical network segments, reducing the potential impact of successful exploitation. Monitoring network traffic for anomalous SNMP activity and implementing intrusion detection systems can help identify potential exploitation attempts. Access control measures should be strengthened by disabling unnecessary SNMP services, implementing strong authentication mechanisms, and limiting SNMP access to trusted management stations only. Organizations should conduct comprehensive vulnerability assessments to identify all affected devices and prioritize remediation efforts based on risk exposure and network criticality. The ATT&CK framework categorizes this vulnerability under T1071.004 for application layer protocol usage and T1059.007 for command and scripting interpreter usage, highlighting the potential for attackers to leverage this vulnerability for further system compromise. Regular security audits and network monitoring should be enhanced to detect unauthorized access attempts and maintain visibility into potential exploitation activities. Given the industrial control system context, organizations must also consider the broader implications for operational technology security and implement appropriate cybersecurity controls to protect against similar vulnerabilities in their industrial network infrastructure.