CVE-2020-8810 in GXDLMS Director
Summary
by MITRE
An issue was discovered in Gurux GXDLMS Director through 8.5.1905.1301. When downloading OBIS codes, it does not verify that the downloaded files are actual OBIS codes and doesn't check for path traversal. This allows the attacker exploiting CVE-2020-8809 to send executable files and place them in an autorun directory, or to place DLLs inside the existing GXDLMS Director installation (run on next execution of GXDLMS Director). This can be used to achieve code execution even if the user doesn't have any add-ins installed.
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Analysis
by VulDB Data Team • 04/06/2024
The vulnerability identified as CVE-2020-8810 affects Gurux GXDLMS Director versions up to 8.5.1905.1301, representing a critical security flaw that combines multiple exploitation vectors to enable unauthorized code execution. This issue specifically targets the application's handling of OBIS code downloads, which are standardized identifiers used in power line communication systems for metering and monitoring purposes. The vulnerability exists within the application's file processing logic where it fails to validate the integrity and type of downloaded files, creating a pathway for malicious actors to inject harmful payloads into the system.
The technical flaw manifests through two primary weaknesses that compound the security risk. First, the application lacks proper validation mechanisms to verify that downloaded files are legitimate OBIS code files, allowing attackers to substitute malicious executables or dynamic link libraries for the expected data. Second, the system does not implement path traversal protection during file operations, enabling attackers to place malicious files in critical system locations such as autorun directories or within the GXDLMS Director installation folder itself. This combination of insufficient input validation and inadequate path restriction creates a dangerous environment where arbitrary code can be executed without user interaction or specialized add-ins.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass full system compromise through a carefully crafted attack sequence. An attacker exploiting CVE-2020-8809, which likely represents a related vulnerability in the download mechanism, can leverage CVE-2020-8810 to achieve persistent code execution by placing malicious DLLs in the installation directory or autorun locations. The vulnerability is particularly concerning because it can be exploited even when users have no additional plugins installed, making it accessible to attackers targeting the base application functionality. This means that any user who downloads OBIS codes from a compromised source could inadvertently trigger the malicious payload during the next execution of GXDLMS Director, potentially leading to complete system takeover.
From a cybersecurity perspective, this vulnerability maps directly to several established frameworks and threat models. The lack of file validation aligns with CWE-22 Path Traversal and CWE-73 Improper Neutralization of Special Elements in Output Used by a Downstream Component, while the failure to verify file integrity corresponds to CWE-121 Heap-based Buffer Overflow and CWE-122 Stack-based Buffer Overflow. The attack pattern follows ATT&CK techniques including T1059 Command and Scripting Interpreter and T1068 Exploitation for Privilege Escalation, with the persistence mechanism falling under T1078 Valid Accounts and T1547 Registry Run Keys. The vulnerability demonstrates the critical importance of input validation and proper file handling in security-critical applications, particularly those used in industrial control systems where unauthorized access can have severe operational consequences. Organizations should immediately implement mitigations including network segmentation, application whitelisting, and comprehensive patch management procedures to address this vulnerability and prevent exploitation attempts.
The vulnerability represents a significant risk to industrial environments that rely on GXDLMS Director for power communication management, as attackers could potentially disrupt critical infrastructure operations or gain unauthorized access to sensitive operational data. The combination of path traversal and insufficient validation creates a particularly dangerous attack surface that can be exploited through simple download operations, making it a prime target for attackers seeking persistent access to industrial control systems.