CVE-2018-18834 in libIEC61850
Summary
by MITRE
An issue has been found in libIEC61850 v1.3. It is a heap-based buffer overflow in BerEncoder_encodeOctetString in mms/asn1/ber_encoder.c.
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Analysis
by VulDB Data Team • 06/03/2023
The vulnerability identified as CVE-2018-18834 represents a critical heap-based buffer overflow within the libIEC61850 library version 1.3, specifically affecting the BerEncoder_encodeOctetString function located in the mms/asn1/ber_encoder.c file. This library serves as a fundamental component in industrial automation systems that implement the IEC 61850 standard for substation automation, making it a prime target for adversaries seeking to compromise critical infrastructure. The buffer overflow occurs during the encoding process of octet string data structures, which are commonly used in communication protocols to transmit binary data between devices in power grid automation environments. The flaw stems from inadequate bounds checking when handling user-supplied data during the BER (Basic Encoding Rules) encoding process, creating a scenario where maliciously crafted input can exceed the allocated memory buffer and overwrite adjacent memory regions.
The technical exploitation of this vulnerability demonstrates a classic heap overflow condition that can lead to arbitrary code execution or system crashes, particularly in environments where the libIEC61850 library is used to process network communications from untrusted sources. The flaw manifests when the BerEncoder_encodeOctetString function fails to properly validate the length of input octet strings against the allocated buffer size, allowing attackers to inject data that overflows the heap allocation. This vulnerability directly maps to CWE-121, which categorizes heap-based buffer overflow conditions, and can be leveraged to achieve privilege escalation or denial-of-service attacks within industrial control systems. The impact is particularly severe in SCADA (Supervisory Control and Data Acquisition) systems and smart grid environments where IEC 61850 compliance is mandatory, as these systems often lack traditional security mitigations found in general-purpose computing environments.
The operational implications of this vulnerability extend beyond simple system instability, as it can enable sophisticated attacks against critical infrastructure networks that rely on IEC 61850 protocols for communication between protective relays, measurement devices, and control systems. Attackers could potentially exploit this weakness to inject malicious data into network communications, manipulate control signals, or cause cascading failures in power grid operations. The vulnerability's presence in a widely-deployed industrial communication library means that numerous organizations across energy, transportation, and manufacturing sectors could be affected, particularly those implementing IEC 61850 in their substation automation systems. Security professionals should consider this vulnerability in the context of ATT&CK framework's T1059.007 technique for executing malicious code through command and scripting interpreters, as well as T1499.004 for network denial of service attacks against industrial control systems. Organizations using this library must prioritize immediate remediation through code updates, input validation enhancements, and network segmentation to prevent exploitation of this heap overflow condition that could result in significant operational disruptions or safety hazards in critical infrastructure environments.