CVE-2021-3445 in libdnf
Summary
by MITRE • 05/19/2021
A flaw was found in libdnf's signature verification functionality in versions before 0.60.1. This flaw allows an attacker to achieve code execution if they can alter the header information of an RPM package and then trick a user or system into installing it. The highest risk of this vulnerability is to confidentiality, integrity, as well as system availability.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 05/22/2021
The vulnerability identified as CVE-2021-3445 resides within the libdnf library's signature verification mechanisms, affecting versions prior to 0.60.1. This flaw represents a critical security weakness in the package management infrastructure that underpins many enterprise and consumer Linux distributions. The libdnf library serves as the foundation for dnf package manager operations, handling package retrieval, installation, and verification processes that are fundamental to system security and integrity.
The technical nature of this vulnerability stems from insufficient validation of RPM package headers during the signature verification process. When an attacker can manipulate the header information of an RPM package, the flawed verification logic fails to properly detect these alterations, allowing maliciously modified packages to appear legitimate. This weakness operates at the intersection of software supply chain security and package management integrity, creating a pathway for privilege escalation and unauthorized code execution. The vulnerability specifically targets the cryptographic verification routines that should ensure package authenticity and prevent tampering, effectively undermining the security model that package managers rely upon.
The operational impact of this vulnerability extends across multiple security domains including confidentiality, integrity, and availability as indicated in the original description. An attacker exploiting this flaw could potentially install malicious software that executes with the privileges of the user or system performing the installation. This capability creates a significant risk for enterprise environments where automated package management systems might be compromised, leading to potential data breaches, system compromise, and lateral movement within network infrastructures. The vulnerability's exploitation requires the attacker to have some level of control over package distribution channels or the ability to perform man-in-the-middle attacks against package repositories.
The security implications of CVE-2021-3445 align with CWE-290 authentication bypass vulnerabilities and can be mapped to ATT&CK techniques related to privilege escalation and supply chain attacks. Organizations relying on dnf package manager and libdnf for system updates face substantial risk when operating vulnerable versions, as this vulnerability could enable attackers to deploy persistent backdoors or malware through seemingly legitimate package installation processes. The flaw demonstrates the critical importance of maintaining up-to-date package management systems and highlights the need for robust supply chain security measures.
Mitigation strategies should prioritize immediate patching of affected systems to libdnf versions 0.60.1 and later, which contain the corrected signature verification logic. System administrators should implement additional verification measures including manual package integrity checks, monitoring for unauthorized package installations, and employing secure package repository configurations. Organizations should also consider implementing network segmentation and access controls to limit potential attack vectors and establish incident response procedures specifically addressing package management security incidents. The vulnerability serves as a reminder of the critical nature of package manager security in maintaining overall system integrity and the necessity of continuous security updates across all system components.