CVE-2018-14817 in V-Server
Summary
by MITRE
Fuji Electric V-Server 4.0.3.0 and prior, An integer underflow vulnerability has been identified, which may allow remote code execution.
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Analysis
by VulDB Data Team • 06/23/2020
The vulnerability identified in Fuji Electric V-Server versions 4.0.3.0 and prior represents a critical integer underflow flaw that exposes systems to remote code execution risks. This vulnerability resides within the server's handling of numeric values during processing operations, where insufficient validation allows malicious actors to manipulate integer variables beyond their valid range. The flaw specifically manifests when the system processes certain input parameters that should be constrained within predefined numerical limits, but instead permits values to wrap around to negative or unexpected ranges.
From a technical perspective, the integer underflow occurs in memory management or data processing routines where unsigned integer variables are decremented below zero, causing the value to overflow into a large positive number. This behavior creates exploitable conditions in buffer operations, memory allocation routines, or loop control structures where the underflowed value is used as a size parameter or index. The vulnerability enables attackers to manipulate program flow by controlling the execution path through invalid memory access patterns, potentially leading to arbitrary code execution on the target system.
The operational impact of this vulnerability extends beyond simple remote code execution to encompass complete system compromise and potential lateral movement within network environments. Attackers can leverage this weakness to gain unauthorized access to industrial control systems, potentially disrupting critical infrastructure operations and compromising safety protocols. The remote nature of the exploit means that attackers do not require physical access to the device, making it particularly dangerous in industrial settings where V-Server systems control manufacturing processes, power distribution, or other critical operations.
Security professionals should recognize this vulnerability as mapping to CWE-191, which specifically addresses integer underflow conditions in software implementations. The attack surface aligns with ATT&CK technique T1059.007 for command and scripting interpreter, as successful exploitation would likely involve executing malicious commands through the compromised system. Additionally, this vulnerability demonstrates characteristics of T1210 for exploitation of remote services, as the remote code execution capability enables attackers to establish persistent access to industrial control environments.
Mitigation strategies should include immediate patching of affected V-Server systems to the latest firmware versions provided by Fuji Electric, along with network segmentation to limit access to these critical systems. Implementing network monitoring solutions to detect anomalous traffic patterns and unauthorized access attempts can help identify exploitation attempts. Organizations should also consider implementing additional security controls such as disabling unnecessary services, applying principle of least privilege access controls, and conducting regular vulnerability assessments to identify similar weaknesses in industrial control system environments. The vulnerability highlights the importance of proper input validation and integer handling in industrial automation systems where security failures can have significant operational and safety implications.