InfrastructurejSerialComm search-path flaws expose EcoStruxure IT Gateway operators
CISA’s ICSA-20-126-01 bulletin explains how Fazecast’s jSerialComm library and Schneider Electric’s EcoStruxure IT Gateway inherit an uncontrolled search path, letting unsigned DLLs execute as soon as technicians connect to serial equipment.
Editorially reviewed for factual accuracy
High-level summary
CISA advisory ICSA-20-126-01 published on disclosed an uncontrolled search path vulnerability in the jSerialComm library used for serial port communications in Java applications. The vulnerability affects Schneider Electric's EcoStruxure IT Gateway and potentially other products embedding the library, enabling arbitrary code execution when attackers place malicious DLLs in the application's search path.
How the vulnerability works
The vulnerability stems from insecure DLL loading practices:
- Uncontrolled search path (CWE-427): The jSerialComm library loads native DLLs without specifying absolute paths, causing Windows to search multiple locations for required libraries.
- DLL hijacking opportunity: Attackers who can write to directories in the search path (current working directory, PATH directories, or application directory) can substitute malicious DLLs that execute when the application loads.
- Privilege inheritance: Malicious code executes with the same privileges as the vulnerable application, potentially including SYSTEM privileges for service-based deployments.
CVSSv3 base score of 7.8 (HIGH) reflects the local attack vector but significant impact potential.
Affected Products
The vulnerability affects multiple products:
- jSerialComm library: All versions before 2.3 of the Fazecast serial communication library.
- EcoStruxure IT Gateway: Schneider Electric's data center infrastructure management platform versions before 1.8.1.
- Other embedders: Any application embedding vulnerable jSerialComm versions may be affected. If you are affected, audit their software inventory for library usage.
Industrial Control System Context
The vulnerability poses particular risk in ICS environments:
- Serial connectivity: Many industrial devices communicate via serial protocols, making serial libraries common in OT engineering tools and gateways.
- Engineering workstations: Compromised engineering workstations can be used to modify PLC programming or access sensitive process information.
- Gateway pivoting: Data center gateways bridge IT and OT networks, potentially enabling lateral movement between environments.
- Maintenance access: Serial connections often require physical access or trusted network position, but software vulnerabilities can be exploited remotely through social engineering or prior compromise.
Attack Scenarios
Exploitation could occur through several vectors:
- Social engineering: Convincing an engineer to open a project file from a location containing malicious DLLs.
- Network share compromise: Placing malicious DLLs on network shares used by engineering workstations.
- Prior compromise: Using existing access to deposit DLLs in application directories.
- USB/removable media: Delivering malicious files through removable media used for air-gapped systems.
Remediation Steps
If you are affected, implement full remediation:
- Update jSerialComm: Upgrade to version 2.3 or later which addresses the search path vulnerability.
- Update EcoStruxure IT Gateway: Upgrade to version 1.8.1 or later incorporating the fixed library.
- Audit other products: Identify and update other applications using vulnerable jSerialComm versions.
- Restrict write access: Limit write permissions to directories in the DLL search path, particularly application and working directories.
- Monitor DLL loading: Implement detection for suspicious DLL loads in ICS environments.
Software Bill of Materials Implications
This vulnerability highlights the importance of software composition analysis:
- Library visibility: Organizations need visibility into third-party libraries embedded in their software.
- Vendor inquiry: Ask vendors about their use of jSerialComm and other serial communication libraries.
- SBOM requirements: Include library version requirements in procurement specifications and vendor security questionnaires.
Closing analysis
ICSA-20-126-01 shows how vulnerabilities in common libraries can cascade across multiple products. If you are affected, focus on patching while implementing compensating controls and improving visibility into embedded library usage across their software inventory.
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Coverage intelligence
- Published
- Coverage pillar
- Infrastructure
- Source credibility
- 73/100 — medium confidence
- Topics
- ICSA-20-126-01 · jSerialComm · EcoStruxure IT Gateway
- Sources cited
- 3 sources (cisa.gov, cvedetails.com, iso.org)
- Reading time
- 5 min
Documentation
- ICSA-20-126-01: jSerialComm
- CVE Details - Vulnerability Database — CVE Details
- ISO/IEC 27017:2015 — Cloud Service Security Controls — International Organization for Standardization
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