CVE-2001-0072 in GnuPG
Summary
by MITRE
gpg (aka GnuPG) 1.0.4 and other versions imports both public and private keys from public key servers without notifying the user about the private keys, which could allow an attacker to break the web of trust.
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Analysis
by VulDB Data Team • 06/25/2021
The vulnerability described in CVE-2001-0072 affects GNU Privacy Guard version 1.0.4 and earlier, representing a significant flaw in the key management and trust validation mechanisms of this widely-used open-source encryption software. This issue stems from the improper handling of key imports from public key servers, where the software automatically processes and imports both public and private keys without alerting users to the presence of private keys in the imported data. The vulnerability exists within the core functionality of GnuPG's key server synchronization capabilities, which are essential for maintaining the web of trust model that underpins the system's security architecture.
The technical flaw manifests in the software's import routine where it fails to distinguish between public and private key components during the key server synchronization process. When GnuPG connects to public key servers to retrieve and update key rings, it indiscriminately imports all available keys without user notification or explicit consent for private key components. This behavior violates fundamental security principles and creates a scenario where an attacker could potentially manipulate the key import process to introduce malicious private keys or exploit the lack of user awareness to compromise the trust model. The vulnerability directly relates to CWE-213, which addresses information exposure through improper handling of sensitive data, and represents a failure in proper input validation and user consent mechanisms.
The operational impact of this vulnerability extends beyond simple privacy concerns to potentially undermine the entire web of trust infrastructure that GnuPG relies upon for secure communications. When private keys are imported without user knowledge, it creates opportunities for man-in-the-middle attacks where adversaries can subvert the trust relationships between users and their cryptographic identities. The web of trust model depends on users being aware of key changes and having control over their key imports, making this vulnerability particularly dangerous as it allows unauthorized parties to manipulate the trust relationships without detection. This flaw could enable attackers to impersonate legitimate users, decrypt communications, or otherwise compromise the security guarantees that GnuPG is designed to provide, effectively weakening the cryptographic security posture of any system relying on affected versions of the software.
Mitigation strategies for this vulnerability require immediate software updates to versions that properly handle key imports and implement user notifications for private key components. Organizations should disable automatic key server synchronization features until proper configuration can be implemented, and establish strict key validation procedures that require manual verification of imported keys. The fix should include implementing explicit user consent mechanisms for private key imports and proper logging of all key import activities to maintain audit trails. This vulnerability also highlights the importance of adhering to security best practices outlined in the NIST SP 800-53 security controls, particularly those related to key management and access control. The remediation process should involve comprehensive key revocation procedures for any compromised trust relationships and re-establishment of trust through proper key verification processes, ensuring that the web of trust remains intact while addressing the specific vulnerability in key import handling.