ISO 15118 Security Vulnerabilities
Comprehensive analysis of security vulnerabilities in the ISO 15118 Vehicle-to-Grid communication protocol
Security Alert
ISO 15118 is a complex protocol that enables advanced communication between electric vehicles and charging infrastructure. While it provides significant benefits like Plug & Charge functionality and bidirectional power transfer, its complexity introduces several security challenges. This analysis examines the key vulnerabilities in the ISO 15118 protocol, their potential impact, and recommended mitigation strategies.
Security Architecture Overview
ISO 15118 relies on a Public Key Infrastructure (PKI) for security, using digital certificates and TLS for secure communication. The security architecture includes:
- TLS Communication: Secure channel between the Electric Vehicle Communication Controller (EVCC) and Supply Equipment Communication Controller (SECC)
- Certificate-Based Authentication: Contract certificates for Plug & Charge functionality
- XML Digital Signatures: Message integrity and authenticity verification
- Certificate Provisioning: Process for installing contract certificates in vehicles
Despite this robust security architecture, several vulnerabilities have been identified that could compromise the security of ISO 15118 implementations if not properly addressed.
Severity Classification
Vulnerabilities are classified according to their potential impact and exploitation difficulty:
| Severity | Description |
|---|---|
Critical | Vulnerabilities that can lead to complete system compromise, unauthorized charging, or financial fraud |
High | Vulnerabilities that can significantly impact security but may require specific conditions or access |
Medium | Vulnerabilities that pose moderate risk and may be mitigated by other security controls |
Low | Vulnerabilities that pose minimal risk but should still be addressed |
Key Vulnerabilities
Improper validation of the certificate chain can allow attackers to use forged certificates for authentication, potentially enabling unauthorized charging sessions.
Attack Vectors
- An attacker could create a malicious certificate that appears valid but is not properly chained to a trusted root
- Implementation flaws in certificate validation logic can lead to acceptance of invalid certificates
- Lack of proper revocation checking can allow use of compromised certificates
Technical Details
Some implementations fail to properly validate the entire certificate chain back to a trusted root CA. This can occur due to incomplete path validation, failure to check certificate revocation status, or improper handling of certificate extensions.
Impact
Unauthorized access to charging services, potential for financial fraud, and compromise of the Plug & Charge authentication system.
Mitigation
Implement strict certificate chain validation according to RFC 5280, including proper path validation, revocation checking (CRL/OCSP), and validation of critical extensions.
References
- CVE-2021-27513
- ISO 15118-2:2014 Section 8.2.3
- RFC 5280 - Internet X.509 Public Key Infrastructure Certificate
Attackers can force the use of weaker TLS versions or cipher suites, potentially compromising the secure channel between EVCC and SECC.
Attack Vectors
- Man-in-the-middle attacks during TLS handshake
- Protocol manipulation to force fallback to weaker encryption
- Implementation flaws in TLS version negotiation
Technical Details
ISO 15118-2 specifies TLS 1.2, but some implementations allow fallback to TLS 1.0 or 1.1, which have known vulnerabilities. Additionally, some implementations accept weak cipher suites that can be broken with sufficient computational resources.
Impact
Compromise of the secure communication channel, potentially leading to eavesdropping on sensitive data, message tampering, or session hijacking.
Mitigation
Enforce TLS 1.2+ with strong cipher suites only, implement proper version negotiation, and regularly update TLS libraries to address known vulnerabilities.
References
- BEAST attack (CVE-2011-3389)
- POODLE attack (CVE-2014-3566)
- ISO 15118-2:2014 Section 8.4.2
Vulnerabilities in the contract certificate installation process can allow unauthorized installation of malicious certificates.
Attack Vectors
- Man-in-the-middle attacks during certificate provisioning
- Exploitation of weak authentication in the certificate installation process
- Social engineering to trick users into installing malicious certificates
Technical Details
The certificate installation process relies on a shared secret (PCID) that may be transmitted insecurely or generated with insufficient entropy. Additionally, the process lacks strong user confirmation mechanisms, potentially allowing silent installation of unauthorized certificates.
Impact
Installation of fraudulent contract certificates, enabling unauthorized charging sessions and financial fraud.
Mitigation
Implement secure out-of-band PCID exchange, enforce strong entropy requirements for PCID generation, and require explicit user confirmation for certificate installation.
References
- ISO 15118-2:2014 Section 8.3.4
- Hubject Security Research 2019
XML Signature Wrapping (XSW) attacks can be used to manipulate signed XML messages while preserving valid signatures.
Attack Vectors
- Injection of malicious content into signed XML messages
- Exploitation of XML parser behavior differences
- Manipulation of XML references and namespaces
Technical Details
ISO 15118 uses XML signatures to ensure message integrity and authenticity. However, improper validation of the relationship between the signature and the message content can allow attackers to inject malicious content while maintaining a valid signature. This occurs when the signature verification process does not properly ensure that the signed content is actually the content being processed.
Impact
Message tampering, potential for unauthorized charging, manipulation of charging parameters, or denial of service.
Mitigation
Implement XML signature validation according to best practices, including strict schema validation, proper canonicalization, and validation of the entire message structure.
References
- XML Signature Wrapping Attacks (McIntosh and Austel, 2005)
- ISO 15118-2:2014 Section 8.4.3
- W3C XML Signature Best Practices
Contract certificates contain identifiers that can be used to track users across charging sessions and locations.
Attack Vectors
- Collection and correlation of contract certificate data
- Unauthorized access to charging session logs
- Network traffic analysis
Technical Details
Contract certificates contain the e-mobility account identifier (EMAID) which uniquely identifies the user's charging contract. This identifier is transmitted during every charging session and can be used to track a user's charging behavior across different locations and times.
Impact
User privacy violation, potential for tracking and profiling of EV users, compliance issues with privacy regulations like GDPR.
Mitigation
Implement privacy-preserving authentication mechanisms, such as anonymous credentials or attribute-based authentication. Minimize data collection and implement proper data protection measures.
References
- ISO 15118-2:2014 Section 8.3.3
- GDPR Article 5 - Principles relating to processing of personal data
- Privacy in Vehicle-to-Grid Interactions (Höfer et al., 2013)
Attackers can cause denial of service by overwhelming the SECC with invalid certificates that require resource-intensive validation.
Attack Vectors
- Sending multiple invalid certificates in rapid succession
- Crafting certificates that trigger worst-case validation paths
- Exploiting lack of rate limiting in certificate processing
Technical Details
Certificate validation is computationally expensive, especially when checking revocation status via OCSP or CRLs. An attacker can exploit this by sending multiple invalid certificates, forcing the SECC to perform resource-intensive validation operations that can exhaust system resources.
Impact
Denial of service for legitimate charging sessions, potential system crashes, or degraded performance of charging infrastructure.
Mitigation
Implement rate limiting for certificate validation requests, optimize certificate validation processes, and implement resource allocation limits to prevent resource exhaustion.
References
- ISO 15118-2:2014 Section 8.2.3
- DoS Attacks on PKI (Boneh and Shoup, 2020)
Inadequate protection of private keys in the EVCC can lead to key extraction and impersonation attacks.
Attack Vectors
- Physical access to the vehicle's communication module
- Exploitation of software vulnerabilities to access key storage
- Side-channel attacks against cryptographic operations
Technical Details
Private keys used for TLS and contract certificate authentication must be securely stored to prevent extraction. However, many implementations store these keys in regular file systems or memory without adequate protection, making them vulnerable to extraction through various attack methods.
Impact
Extraction of private keys would allow an attacker to impersonate the vehicle, potentially enabling unauthorized charging sessions and financial fraud.
Mitigation
Use hardware security modules (HSMs) or trusted platform modules (TPMs) for key storage, implement secure boot and code signing, and use memory protection mechanisms to prevent unauthorized access to cryptographic material.
References
- ISO 15118-2:2014 Section 8.3.2
- FIPS 140-2 Security Requirements for Cryptographic Modules
- Side-Channel Attacks on Automotive Systems (Checkoway et al., 2015)
Vulnerabilities in session management can allow attackers to hijack active charging sessions.
Attack Vectors
- Man-in-the-middle attacks to intercept and modify session data
- Session identifier prediction or brute forcing
- Race conditions in session establishment
Technical Details
ISO 15118 uses session identifiers to maintain state between the EVCC and SECC. Weaknesses in session identifier generation, validation, or protection can allow attackers to hijack active sessions. Additionally, lack of continuous authentication throughout the session can create windows of opportunity for session takeover.
Impact
Unauthorized control of charging sessions, potential for energy theft, manipulation of charging parameters, or denial of service.
Mitigation
Implement secure session management with strong session identifiers, continuous authentication, and proper session termination. Use TLS to protect session data in transit.
References
- ISO 15118-2:2014 Section 8.4.3
- OWASP Session Management Cheat Sheet
- Secure Session Management in Web Applications (Steel et al., 2006)
Conclusion
ISO 15118 provides significant benefits for EV charging, but its security depends on proper implementation and ongoing vigilance. The vulnerabilities identified in this analysis highlight the importance of following security best practices, implementing robust PKI infrastructure, and maintaining operational security measures.
As the adoption of ISO 15118 increases, particularly with the rollout of Plug & Charge functionality and the transition to ISO 15118-20, addressing these security challenges becomes increasingly important to ensure the integrity, confidentiality, and availability of EV charging infrastructure.
Most Affected Components
- PKI Infrastructure3 vulnerabilities
- EVCC5 vulnerabilities
- SECC6 vulnerabilities
- Communication Layer2 vulnerabilities
- ISO 15118 Implementation Flaws
Analysis of common implementation flaws in ISO 15118 Plug & Charge
- ISO 15118 Protocol Overview
Comprehensive guide to the ISO 15118 Vehicle-to-Grid Communication Interface standard
- OCPP Security Analysis
Security analysis of the Open Charge Point Protocol