CVE-2012-0954 in APT
Summary
by MITRE
APT 0.7.x before 0.7.25 and 0.8.x before 0.8.16, when using the apt-key net-update to import keyrings, relies on GnuPG argument order and does not check GPG subkeys, which might allow remote attackers to install altered packages via a man-in-the-middle (MITM) attack. NOTE: this vulnerability exists because of an incomplete fix for CVE-2012-3587.
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Analysis
by VulDB Data Team • 12/04/2021
The vulnerability identified as CVE-2012-0954 represents a critical security flaw in the Advanced Package Tool (APT) software package management system. This issue affects APT versions 0.7.x prior to 0.7.25 and 0.8.x prior to 0.8.16, specifically when utilizing the apt-key net-update functionality to import keyrings. The vulnerability stems from improper handling of GnuPG argument order and lacks verification of GPG subkeys, creating a significant attack vector that enables remote adversaries to compromise system integrity through man-in-the-middle attacks. The flaw essentially undermines the cryptographic verification mechanisms that APT relies upon to ensure package authenticity and integrity.
The technical implementation of this vulnerability involves a fundamental flaw in how APT processes GnuPG key imports during network operations. When the apt-key net-update command executes, it fails to properly validate the GPG subkeys associated with the imported keyrings, relying instead on the order of GnuPG arguments that may be manipulated by an attacker. This improper argument handling creates a scenario where an attacker positioned in a man-in-the-middle position can intercept network traffic and substitute maliciously altered package signatures. The vulnerability's root cause is directly linked to an incomplete remediation of CVE-2012-3587, indicating that previous fixes were insufficient to address all aspects of the cryptographic verification process.
The operational impact of CVE-2012-0954 extends beyond simple package management compromise, as it fundamentally undermines the trust model that APT systems rely upon for secure software distribution. When exploited, this vulnerability allows attackers to install altered packages that appear legitimate to the system, potentially leading to privilege escalation, backdoor installation, or complete system compromise. The man-in-the-middle attack vector is particularly dangerous because it can be executed without requiring direct access to the target system, making it an attractive attack method for adversaries seeking to compromise multiple systems simultaneously. This vulnerability affects Linux distributions that utilize APT for package management, including Debian and Ubuntu systems, potentially exposing thousands of vulnerable endpoints.
Security professionals should recognize this vulnerability as a direct consequence of CWE-310, which addresses cryptographic issues related to improper implementation of cryptographic protocols. The flaw also aligns with ATT&CK technique T1059, specifically focusing on the manipulation of system processes and package management tools to achieve persistence and privilege escalation. Organizations should immediately implement mitigations including updating to APT versions 0.7.25 or 0.8.16, which contain the proper cryptographic verification mechanisms. Additionally, administrators should consider implementing network-level controls such as DNS security extensions and certificate pinning to prevent man-in-the-middle attacks. The vulnerability demonstrates the importance of comprehensive security testing and the necessity of thorough validation when implementing cryptographic fixes to ensure all attack vectors are properly addressed.