CVE-2016-1252 in apt
Summary
by MITRE
The apt package in Debian jessie before 1.0.9.8.4, in Debian unstable before 1.4~beta2, in Ubuntu 14.04 LTS before 1.0.1ubuntu2.17, in Ubuntu 16.04 LTS before 1.2.15ubuntu0.2, and in Ubuntu 16.10 before 1.3.2ubuntu0.1 allows man-in-the-middle attackers to bypass a repository-signing protection mechanism by leveraging improper error handling when validating InRelease file signatures.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 10/16/2024
The vulnerability identified as CVE-2016-1252 affects the advanced package tool apt package manager across multiple Debian and Ubuntu distributions, representing a critical security flaw in the package management infrastructure that underpins countless Linux systems. This vulnerability specifically targets the repository-signing protection mechanism that ensures package integrity and authenticity, creating a pathway for malicious actors to compromise system security through man-in-the-middle attacks. The flaw exists in the error handling process during InRelease file signature validation, where improper error management allows attackers to bypass critical security checks that should prevent the installation of unsigned or tampered packages.
The technical implementation of this vulnerability stems from inadequate validation procedures within the apt package manager's signature verification process. When apt encounters repository metadata in the form of InRelease files, it should rigorously validate the cryptographic signatures to ensure that packages originate from legitimate sources and have not been modified during transit. However, the vulnerability allows attackers to exploit a condition where error handling fails to properly reject malformed or unsigned InRelease files, effectively permitting the installation of packages that should have been rejected due to invalid signatures. This weakness aligns with CWE-248, an improper exception handling vulnerability, where the system fails to properly handle exceptional conditions during cryptographic validation processes.
The operational impact of this vulnerability extends far beyond a simple security bypass, as it fundamentally undermines the trust model that package managers rely upon to maintain system integrity. Attackers can leverage this weakness to inject malicious packages into the update process, potentially compromising entire systems through supply chain attacks. The vulnerability affects systems running Debian jessie versions prior to 1.0.9.8.4, Debian unstable versions before 1.4~beta2, Ubuntu 14.04 LTS before 1.0.1ubuntu2.17, Ubuntu 16.04 LTS before 1.2.15ubuntu0.2, and Ubuntu 16.10 before 1.3.2ubuntu0.1, representing a substantial portion of the Linux ecosystem. This vulnerability directly relates to the attack pattern described in the MITRE ATT&CK framework under T1068, which covers 'Exploitation for Privilege Escalation' through the compromise of system update mechanisms.
The implications of this vulnerability are particularly severe because package managers are integral to system maintenance and security, making them prime targets for attackers seeking persistent access to compromised systems. When an attacker successfully bypasses the signature validation, they can introduce backdoors, rootkits, or other malicious software that will be automatically installed during routine system updates, creating a stealthy persistence mechanism. The vulnerability also impacts the broader security posture of organizations relying on these systems, as it can lead to unauthorized access to sensitive data and systems. Organizations using affected versions of these operating systems should immediately implement mitigations including patching to the latest versions, implementing additional repository verification mechanisms, and monitoring for unauthorized package installations. The vulnerability demonstrates the critical importance of robust cryptographic error handling in security-critical systems and serves as a reminder that even minor flaws in validation logic can have catastrophic security implications.