CVE-2019-7304 in snapd
Summary
by MITRE
Canonical snapd before version 2.37.1 incorrectly performed socket owner validation, allowing an attacker to run arbitrary commands as root. This issue affects: Canonical snapd versions prior to 2.37.1.
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Analysis
by VulDB Data Team • 12/26/2024
The vulnerability identified as CVE-2019-7304 represents a critical privilege escalation flaw in Canonical's snapd package manager system. This issue stems from improper socket owner validation mechanisms that were implemented in snapd versions prior to 2.37.1, creating a dangerous security loophole that could be exploited by malicious actors to execute arbitrary commands with root privileges. The flaw specifically targets the communication layer between snapd and its various components, where socket ownership verification was insufficient to prevent unauthorized access.
The technical implementation of this vulnerability occurs within snapd's socket validation logic where the system fails to properly verify the ownership and permissions of Unix domain sockets used for inter-process communication. When snapd creates or manages these sockets, it does not adequately enforce proper ownership checks that should prevent non-root processes from establishing connections that could lead to privilege escalation. This weakness allows attackers to manipulate socket permissions or create malicious socket connections that bypass normal access controls, ultimately enabling them to execute code with elevated privileges. The flaw operates at the system-level communication interface, making it particularly dangerous as it can be exploited without requiring local user credentials or prior access to the system.
The operational impact of CVE-2019-7304 is severe and far-reaching across systems running affected versions of snapd. Any attacker who can gain access to a system with vulnerable snapd installations can potentially escalate privileges to root level, gaining complete control over the affected machine. This vulnerability affects Linux distributions that utilize Canonical's snap package management system, including Ubuntu and other derivatives that rely on snapd for software deployment and management. The exploitation of this flaw could lead to complete system compromise, data exfiltration, persistence mechanisms establishment, and further lateral movement within network environments where such systems exist. The vulnerability's severity is compounded by the fact that snapd is a core system component that runs with elevated privileges and is responsible for managing snap packages, making it an attractive target for attackers seeking system-level access.
Mitigation strategies for CVE-2019-7304 primarily involve upgrading to snapd version 2.37.1 or later, which contains the necessary patches to address the socket owner validation flaw. Organizations should implement immediate remediation procedures to update all affected systems and verify that the upgrade has been successfully applied. Additionally, system administrators should monitor for any signs of exploitation attempts and consider implementing network-based detection measures to identify potential exploitation attempts. The vulnerability aligns with CWE-276, which addresses improper file permissions, and relates to ATT&CK technique T1068, which covers local privilege escalation. Security teams should also consider implementing least privilege principles for snapd operations and regularly audit socket permissions to prevent similar issues from occurring in other system components. The fix implemented in version 2.37.1 includes enhanced socket ownership validation that properly verifies process ownership before allowing communication, thereby closing the privilege escalation pathway that existed in earlier versions.