CVE-2017-12113 in JSON-RPC
Summary
by MITRE
An exploitable improper authorization vulnerability exists in admin_nodeInfo API of cpp-ethereum's JSON-RPC (commit 4e1015743b95821849d001618a7ce82c7c073768). A JSON request can cause an access to the restricted functionality resulting in authorization bypass. An attacker can send JSON to trigger this vulnerability.
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Analysis
by VulDB Data Team • 02/02/2023
The CVE-2017-12113 vulnerability represents a critical authorization bypass flaw within the cpp-ethereum implementation of the JSON-RPC interface, specifically affecting the admin_nodeInfo API endpoint. This vulnerability stems from inadequate access control mechanisms that fail to properly validate user permissions before granting access to sensitive administrative functions. The flaw exists in the commit 4e1015743b95821849d001618a7ce82c7c073768 of the cpp-ethereum codebase, which demonstrates how insufficient input validation and authorization checks can create pathways for unauthorized access to critical system information. The vulnerability operates by allowing any remote attacker to submit specially crafted JSON requests that bypass the intended authorization controls, effectively granting access to restricted administrative functionality that should only be available to authenticated administrators.
The technical implementation of this vulnerability involves a flaw in the JSON-RPC handler logic where the admin_nodeInfo API endpoint fails to properly verify the authentication status of incoming requests. When a JSON-RPC request is processed, the system should validate whether the requester possesses the necessary administrative privileges before executing the node information retrieval function. However, the flawed implementation allows unauthenticated or improperly authenticated users to access this endpoint, enabling them to obtain detailed information about the Ethereum node configuration, network topology, and potentially sensitive system parameters. This misconfiguration creates a pathway for attackers to gather intelligence about the target system, which can be leveraged for further exploitation attempts. The vulnerability aligns with CWE-285, which addresses improper authorization issues, and represents a classic example of how insufficient access control validation can lead to privilege escalation and unauthorized system access.
The operational impact of CVE-2017-12113 extends beyond simple information disclosure, as it provides attackers with valuable reconnaissance data that can facilitate more sophisticated attacks. An attacker who successfully exploits this vulnerability can obtain node configuration details, network addresses, and other system information that could be used to plan targeted attacks against the Ethereum network infrastructure. This information disclosure can enable adversaries to identify potential attack vectors, understand network topology, and potentially exploit other related vulnerabilities within the same system. The vulnerability also demonstrates how JSON-RPC interfaces, when improperly secured, can become entry points for attackers seeking to gain unauthorized access to blockchain infrastructure. The attack surface is particularly concerning in distributed blockchain networks where node information can reveal critical details about network participation and system configuration.
Mitigation strategies for this vulnerability require immediate implementation of proper authentication and authorization checks within the JSON-RPC interface. System administrators should ensure that all administrative endpoints, including admin_nodeInfo, require proper authentication tokens or credentials before execution. The fix involves implementing robust access control mechanisms that validate user permissions at the API level, ensuring that only authenticated administrators can access sensitive node information. Organizations should also consider implementing additional security controls such as rate limiting, IP whitelisting, and network segmentation to reduce the attack surface. The remediation process should include thorough code review of all JSON-RPC endpoints to identify similar authorization flaws and ensure that proper authentication mechanisms are in place. This vulnerability highlights the importance of following security best practices in blockchain implementations and aligns with ATT&CK techniques related to privilege escalation and reconnaissance, emphasizing the need for comprehensive security testing and validation of administrative interfaces in distributed systems.