CVE-2015-7939 in VisiLogic OPLC IDE
Summary
by MITRE
Heap-based buffer overflow in Unitronics VisiLogic OPLC IDE before 9.8.09 allows remote attackers to execute arbitrary code via a long vlp filename.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 06/06/2018
The vulnerability identified as CVE-2015-7939 represents a critical heap-based buffer overflow flaw within Unitronics VisiLogic OPLC IDE software version 9.8.08 and earlier. This vulnerability resides in the handling of vlp filename parameters during the software's operation, creating a potential pathway for remote code execution attacks. The affected system operates within industrial control environments where programmable logic controllers and visualization software play crucial roles in automation and process control systems. The buffer overflow occurs when the software processes excessively long vlp filenames without proper bounds checking, leading to memory corruption that can be exploited by malicious actors.
The technical implementation of this vulnerability stems from inadequate input validation mechanisms within the VisiLogic IDE's file handling routines. When a maliciously crafted vlp filename exceeds the allocated buffer size, the software fails to properly terminate or truncate the input data, resulting in memory overwrite conditions. This heap-based overflow specifically targets the software's memory allocation patterns, where the vulnerable code does not perform sufficient bounds checking before copying filename data into internal buffers. The flaw aligns with CWE-121, which categorizes heap-based buffer overflow conditions as a fundamental memory safety issue that can lead to arbitrary code execution. Attackers can leverage this vulnerability by crafting specially formatted vlp files with excessively long filenames that trigger the buffer overflow during normal software operation, potentially allowing them to execute malicious code with the privileges of the affected application.
The operational impact of CVE-2015-7939 extends beyond typical software security concerns into critical infrastructure domains where industrial control systems operate. The remote execution capability means that attackers can potentially compromise control systems from external networks without requiring physical access to the industrial facilities. This vulnerability particularly affects environments using Unitronics PLCs and visualization software, which are commonly deployed in manufacturing plants, process control facilities, and automation systems where continuous operation is critical. The attack surface includes scenarios where the IDE software might be accessed over network connections or when vlp files are transferred between systems, making the vulnerability exploitable in both local and remote attack scenarios. Organizations implementing the affected software may face significant operational disruptions, potential safety hazards, and regulatory compliance issues if such attacks are successfully executed, as they could lead to unauthorized modifications of control logic or complete system compromise.
Mitigation strategies for CVE-2015-7939 should prioritize immediate software updates to version 9.8.09 or later, which contain the necessary patches addressing the buffer overflow condition. Organizations should implement network segmentation and access controls to limit exposure of the affected software to untrusted networks and users. Security monitoring should focus on detecting unusual file transfer activities or attempts to access the IDE software with malformed vlp filenames. The vulnerability demonstrates the importance of input validation and bounds checking in industrial control system software, aligning with ATT&CK technique T1059.007 for execution through scripting and T1210 for exploitation of remote services. Regular security assessments of industrial control systems should include vulnerability scanning for similar buffer overflow conditions, particularly in legacy software environments where patching may be challenging. System administrators should also consider implementing network-based intrusion detection systems to monitor for exploitation attempts targeting this specific vulnerability, as the attack pattern involves predictable buffer overflow exploitation techniques that can be detected through network traffic analysis.