CVE-2012-2388 in strongSwan
Summary
by MITRE
The GMP Plugin in strongSwan 4.2.0 through 4.6.3 allows remote attackers to bypass authentication via a (1) empty or (2) zeroed RSA signature, aka "RSA signature verification vulnerability."
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Analysis
by VulDB Data Team • 12/05/2021
The vulnerability identified as CVE-2012-2388 represents a critical weakness in the GMP Plugin component of strongSwan VPN software versions 4.2.0 through 4.6.3. This flaw resides in the cryptographic signature verification process, specifically affecting the RSA signature validation mechanism that is fundamental to the integrity and authenticity of secure communications. The vulnerability stems from inadequate validation of RSA signatures during the authentication process, creating a pathway for malicious actors to exploit the system's trust model.
The technical implementation of this vulnerability occurs when the GMP Plugin fails to properly verify RSA signatures, allowing attackers to submit either empty signatures or signatures with zeroed values that are accepted as valid authentications. This represents a classic cryptographic weakness where the validation logic does not adequately check for null or zero-length signature values, effectively bypassing the entire signature verification process. The flaw operates at the cryptographic protocol level, undermining the fundamental security assumptions that secure communication protocols rely upon for authentication and data integrity.
The operational impact of this vulnerability is severe and far-reaching within network security infrastructure. Remote attackers can exploit this weakness to gain unauthorized access to VPN services without proper authentication credentials, potentially compromising entire network perimeters. This vulnerability directly affects the confidentiality, integrity, and availability of protected communications, as it allows attackers to establish secure connections without legitimate authentication. The implications extend beyond simple unauthorized access to include potential data exfiltration, man-in-the-middle attacks, and complete compromise of the VPN infrastructure that relies on strongSwan's GMP Plugin for cryptographic operations.
Organizations utilizing affected strongSwan versions face significant risk exposure when this vulnerability is present in their network security architecture. The attack vector requires only remote network access to exploit the flaw, making it particularly dangerous as it can be leveraged from external networks without requiring physical access or insider knowledge. This vulnerability aligns with CWE-310, which categorizes cryptographic weaknesses, specifically addressing the lack of proper signature validation in cryptographic implementations. The threat landscape for this vulnerability is particularly concerning given that it affects a core component of IPsec VPN implementations that are widely deployed across enterprise and government networks.
The recommended mitigation strategy involves immediate upgrade to strongSwan versions that have patched this vulnerability, specifically versions beyond 4.6.3 where the RSA signature verification has been properly implemented. Organizations should also implement network segmentation and monitoring to detect anomalous authentication patterns that might indicate exploitation attempts. Additionally, security teams should review and validate all cryptographic implementations within their infrastructure to ensure similar vulnerabilities do not exist in other components. This vulnerability demonstrates the critical importance of proper cryptographic validation and adherence to security standards such as those defined by NIST SP 800-57 for cryptographic key management and signature verification processes.