CVE-2019-3699 in Leap
Summary
by MITRE
UNIX Symbolic Link (Symlink) Following vulnerability in the packaging of privoxy on openSUSE Leap 15.1, Factory allows local attackers to escalate from user privoxy to root. This issue affects: openSUSE Leap 15.1 privoxy version 3.0.28-lp151.1.1 and prior versions. openSUSE Factory privoxy version 3.0.28-2.1 and prior versions.
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Analysis
by VulDB Data Team • 03/26/2024
The vulnerability CVE-2019-3699 represents a critical privilege escalation flaw in the privoxy package implementation on openSUSE systems, specifically affecting versions prior to 3.0.28-lp151.1.1 and 3.0.28-2.1 respectively. This issue stems from improper handling of symbolic links during the packaging process, creating a path traversal condition that allows local attackers to manipulate file permissions and execute arbitrary code with elevated privileges. The vulnerability specifically targets the privoxy proxy service which typically runs with reduced privileges but can be exploited to gain root access through carefully crafted symbolic link attacks.
The technical flaw manifests when the privoxy packaging process fails to properly validate or sanitize symbolic link references during installation or configuration file processing. This creates a scenario where an attacker can establish a symbolic link pointing to a critical system file or directory, then manipulate the privilege escalation process to gain root access. The vulnerability is classified as a symlink following issue that directly relates to CWE-59 and CWE-22, representing path traversal and symbolic link manipulation weaknesses. The flaw operates at the operating system level where the packaging system does not adequately enforce proper access controls or validate the integrity of symbolic link targets during the installation process.
The operational impact of this vulnerability is severe as it allows local attackers to escalate privileges from the standard privoxy user account to the root user level without requiring additional authentication or external exploitation. This creates a significant security risk for systems running affected versions of privoxy, particularly in environments where multiple users have access to the system. Attackers can leverage this vulnerability to gain complete system control, potentially leading to data exfiltration, system compromise, or further lateral movement within a network. The vulnerability affects the core packaging and installation mechanisms of the privoxy service, making it particularly dangerous as it undermines the fundamental security assumptions of the package management system.
Mitigation strategies for CVE-2019-3699 involve immediate patching of the privoxy package to versions 3.0.28-lp151.1.1 or later for openSUSE Leap 15.1 and 3.0.28-2.1 or later for openSUSE Factory. System administrators should also implement proper file system permissions and ensure that symbolic links are properly validated during package installations. The ATT&CK framework categorizes this vulnerability under privilege escalation techniques, specifically targeting the T1068 - Exploitation for Privilege Escalation tactic. Organizations should conduct comprehensive vulnerability assessments to identify systems running affected versions and implement monitoring for suspicious file system activities that might indicate exploitation attempts. Additionally, implementing proper system hardening practices including restricted package installation permissions and regular security audits can help prevent exploitation of similar vulnerabilities in the future.