CVE-2019-19930 in libIEC61850
Summary
by MITRE
In libIEC61850 1.4.0, MmsValue_newOctetString in mms/iso_mms/common/mms_value.c has an integer signedness error that can lead to an attempted excessive memory allocation.
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Analysis
by VulDB Data Team • 03/16/2024
The vulnerability identified as CVE-2019-19930 resides within the libIEC61850 library version 1.4.0, specifically in the MmsValue_newOctetString function located in the file mms/iso_mms/common/mms_value.c. This issue represents a critical security flaw that stems from a fundamental error in how integer values are handled during memory allocation processes. The vulnerability manifests as a signedness error that can potentially allow attackers to manipulate memory allocation requests, leading to unintended system behavior.
The technical flaw occurs when the function processes octet string data structures, where an integer variable intended to represent the size of memory to be allocated is improperly treated as signed rather than unsigned. This misclassification creates a scenario where negative values can be passed to memory allocation functions, potentially causing the system to attempt allocating an excessive amount of memory or even trigger memory corruption. The flaw directly relates to CWE-190, which encompasses integer overflow and signedness errors, and can be classified under the broader category of CWE-129 as an improper validation of array index or buffer length.
The operational impact of this vulnerability extends significantly within industrial control systems and communication environments that rely on IEC 61850 standards for substation automation. When exploited, the vulnerability can lead to denial of service conditions where legitimate system operations are disrupted due to excessive memory consumption or allocation failures. In more severe scenarios, the improper memory handling could potentially lead to memory corruption that might be exploited for arbitrary code execution, particularly in environments where the affected library is used to process untrusted data from network sources. The vulnerability affects systems that implement MMS (Manufacturing Message Specification) protocols, which are fundamental to power system automation and other industrial communication frameworks.
Mitigation strategies for this vulnerability require immediate attention from system administrators and developers working with libIEC61850 implementations. The primary recommendation involves upgrading to a patched version of the library where the integer signedness error has been corrected and proper validation of input parameters has been implemented. Additionally, developers should ensure that all integer values used in memory allocation contexts are properly validated and constrained to prevent negative values from being processed. The implementation of input sanitization measures and proper boundary checks aligns with ATT&CK technique T1082, which focuses on system information discovery, and T1499, which addresses network denial of service attacks. Organizations should also consider implementing network segmentation and access controls to limit exposure of systems that utilize vulnerable versions of the library, particularly in critical infrastructure environments where IEC 61850 communication protocols are deployed.