CVE-2011-3374 in apt
Summary
by MITRE
It was found that apt-key in apt, all versions, do not correctly validate gpg keys with the master keyring, leading to a potential man-in-the-middle attack.
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Analysis
by VulDB Data Team • 02/27/2024
The vulnerability described in CVE-2011-3374 affects the apt package management system across all versions, specifically targeting the apt-key utility's handling of GPG key validation processes. This flaw resides in the core security mechanism that ensures package integrity and authenticity when software is installed through the advanced package tool. The issue stems from improper validation of GPG keys within the master keyring, creating a significant security gap that adversaries could exploit to compromise system integrity.
The technical flaw manifests when apt-key attempts to verify GPG signatures using the master keyring, where the validation process fails to properly authenticate the key's legitimacy. This weakness allows malicious actors to potentially insert forged GPG keys that appear valid to the system, enabling them to sign malicious packages that would be accepted as legitimate by the package manager. The vulnerability operates at the trust validation layer, where the system should verify key authenticity but instead accepts potentially compromised keys due to insufficient cryptographic validation checks. This represents a fundamental breakdown in the public key infrastructure implementation within the Debian-based package management ecosystem.
The operational impact of this vulnerability extends beyond simple package installation risks, as it fundamentally undermines the security model that protects Linux systems from malicious software. An attacker who successfully exploits this vulnerability could inject malicious packages into repositories, potentially compromising entire networks of systems that rely on apt for package management. The man-in-the-middle attack vector becomes particularly dangerous because it operates at the point of package verification, where users expect the highest level of security assurance. Systems using apt for package management are vulnerable to supply chain attacks, where trusted repositories could be compromised to deliver malicious software without detection.
Mitigation strategies for this vulnerability require immediate implementation of proper key validation procedures and system updates to patched versions of apt. Organizations should conduct comprehensive audits of their GPG key management practices, ensuring that all keys are properly validated through multiple verification methods before being accepted into the master keyring. The recommended approach involves implementing strict key fingerprint verification processes and establishing secure channels for key distribution. Additionally, system administrators should consider implementing automated monitoring for unauthorized key additions and establish robust key management policies that align with industry standards such as those specified in the Common Weakness Enumeration framework under CWE-310. This vulnerability highlights the critical importance of cryptographic validation in package management systems and aligns with ATT&CK techniques related to privilege escalation and supply chain attacks.