CVE-2020-8019 in Linux Enterprise Debuginfo
Summary
by MITRE
A UNIX Symbolic Link (Symlink) Following vulnerability in the packaging of syslog-ng of SUSE Linux Enterprise Debuginfo 11-SP3, SUSE Linux Enterprise Debuginfo 11-SP4, SUSE Linux Enterprise Module for Legacy Software 12, SUSE Linux Enterprise Point of Sale 11-SP3, SUSE Linux Enterprise Server 11-SP4-LTSS, SUSE Linux Enterprise Server for SAP 12-SP1; openSUSE Backports SLE-15-SP1, openSUSE Leap 15.1 allowed local attackers controlling the user news to escalate their privileges to root. This issue affects: SUSE Linux Enterprise Debuginfo 11-SP3 syslog-ng versions prior to 2.0.9-27.34.40.5.1. SUSE Linux Enterprise Debuginfo 11-SP4 syslog-ng versions prior to 2.0.9-27.34.40.5.1. SUSE Linux Enterprise Module for Legacy Software 12 syslog-ng versions prior to 3.6.4-12.8.1. SUSE Linux Enterprise Point of Sale 11-SP3 syslog-ng versions prior to 2.0.9-27.34.40.5.1. SUSE Linux Enterprise Server 11-SP4-LTSS syslog-ng versions prior to 2.0.9-27.34.40.5.1. SUSE Linux Enterprise Server for SAP 12-SP1 syslog-ng versions prior to 3.6.4-12.8.1. openSUSE Backports SLE-15-SP1 syslog-ng versions prior to 3.19.1-bp151.4.6.1. openSUSE Leap 15.1 syslog-ng versions prior to 3.19.1-lp151.3.6.1.
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Analysis
by VulDB Data Team • 10/28/2020
The vulnerability identified as CVE-2020-8019 represents a critical privilege escalation flaw within the syslog-ng packaging system of various SUSE and openSUSE Linux distributions. This issue stems from improper handling of symbolic links during the syslog-ng daemon execution process, creating a pathway for local attackers to elevate their privileges from standard user level to root access. The vulnerability specifically affects systems where the syslog-ng service runs with elevated privileges and processes user-generated content without proper sanitization of symbolic link references.
The technical root cause of this vulnerability lies in the improper validation of file paths when processing log data, particularly in scenarios where symbolic links are involved in the logging pipeline. When syslog-ng processes log messages that contain symbolic link references, the system fails to properly resolve or validate these links before executing operations that require elevated privileges. This creates a race condition scenario where an attacker can manipulate symbolic links in such a way that when syslog-ng processes them, it inadvertently executes code with root privileges. The vulnerability manifests when the syslog-ng daemon follows symbolic links without proper access controls or path validation mechanisms, allowing attackers to control the target of these links and potentially execute malicious code with elevated permissions.
This privilege escalation vulnerability has significant operational impact within enterprise environments where syslog-ng is commonly deployed for system monitoring and log aggregation. The attack vector requires local access to the system, meaning an attacker must already have a user account or some form of initial foothold, but the privilege escalation to root level presents a severe security risk. Once an attacker achieves root access through this vulnerability, they can modify system files, install persistent backdoors, exfiltrate sensitive data, or compromise the entire system. The vulnerability affects multiple versions across different SUSE product lines including server editions, point of sale systems, and legacy software modules, indicating a widespread exposure across various deployment scenarios. According to CWE classification, this vulnerability maps to CWE-59, which describes improper handling of symbolic links, and CWE-269, which covers improper privilege management. The ATT&CK framework categorizes this under privilege escalation techniques, specifically T1068 which involves exploiting vulnerabilities to gain higher privileges.
Mitigation strategies for CVE-2020-8019 involve immediate patching of affected syslog-ng versions to the corrected releases specified in the vulnerability advisory. Organizations should prioritize updating all affected systems to the patched versions, particularly focusing on the specific version numbers mentioned in the CVE description for each affected distribution. System administrators should implement additional monitoring to detect unusual symbolic link creation or modification patterns in log processing directories. The recommended approach includes disabling unnecessary symbolic link following capabilities in syslog-ng configuration files, implementing stricter file access controls, and ensuring proper privilege separation between user-level processes and system-level operations. Additionally, organizations should conduct thorough vulnerability assessments to identify any other services or applications that might be similarly vulnerable to symbolic link following attacks, as this type of vulnerability often indicates broader system configuration weaknesses that require comprehensive security hardening measures.