CVE-2015-0840 in dpkg
Summary
by MITRE
The dpkg-source command in Debian dpkg before 1.16.16 and 1.17.x before 1.17.25 allows remote attackers to bypass signature verification via a crafted Debian source control file (.dsc).
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Analysis
by VulDB Data Team • 05/03/2022
The vulnerability identified as CVE-2015-0840 represents a critical security flaw in the Debian package management system's dpkg-source utility. This issue affects versions of dpkg prior to 1.16.16 and 1.17.x prior to 1.17.25, where the dpkg-source command fails to properly validate signature verification mechanisms when processing Debian source control files with the .dsc extension. The flaw enables remote attackers to exploit the package management system by crafting malicious source control files that bypass intended security checks, potentially allowing unauthorized code execution or package tampering within affected systems.
The technical root cause of this vulnerability lies in the insufficient validation of cryptographic signatures within the dpkg-source utility. When processing .dsc files, the command should verify the authenticity and integrity of source packages through proper signature checking mechanisms before accepting them for processing. However, the vulnerable implementation fails to properly enforce these signature verification steps, creating a pathway for attackers to inject malicious content that appears legitimate to the package management system. This weakness specifically manifests in the handling of source control files that contain crafted elements designed to circumvent the signature verification process, allowing attackers to bypass security controls that should prevent unauthorized package modifications.
The operational impact of CVE-2015-0840 extends beyond simple privilege escalation to encompass broader system compromise potential. Attackers exploiting this vulnerability can manipulate package installation processes by submitting forged .dsc files that appear to come from legitimate sources, potentially leading to the installation of malicious software packages on vulnerable systems. This threat is particularly concerning in enterprise environments where automated package management systems rely on dpkg for software distribution and updates. The vulnerability could enable attackers to establish persistent access points through compromised package installations, making it a significant concern for system administrators responsible for maintaining software integrity across multiple systems.
The implications of this vulnerability align with CWE-347, which addresses improper verification of cryptographic signatures, and can be mapped to ATT&CK technique T1195.002 related to Supply Chain Compromise. Organizations running affected versions of dpkg face potential exposure to supply chain attacks where malicious actors could compromise package repositories or individual packages through this signature bypass mechanism. The vulnerability demonstrates a failure in the cryptographic validation process that should be fundamental to package management security, making it particularly dangerous in environments where package integrity is critical for system security. System administrators should prioritize patching affected installations and implementing additional verification measures to protect against exploitation attempts.
Mitigation strategies for CVE-2015-0840 require immediate action to upgrade dpkg to versions 1.16.16 or 1.17.25 and later, which contain the necessary signature verification fixes. Organizations should also implement additional security measures such as verifying package signatures through multiple independent verification methods, monitoring package repositories for suspicious activity, and ensuring that package management systems are configured to enforce strict signature validation. Regular security audits of package management infrastructure should be conducted to identify and remediate similar vulnerabilities in other components of the software supply chain. The vulnerability underscores the importance of maintaining up-to-date security patches and implementing defense-in-depth strategies for package management systems that rely on cryptographic verification for integrity protection.