CVE-2013-1976 in Tomcat
Summary
by MITRE
The (1) tomcat5, (2) tomcat6, and (3) tomcat7 init scripts, as used in the RPM distribution of Tomcat for JBoss Enterprise Web Server 1.0.2 and 2.0.0, and Red Hat Enterprise Linux 5 and 6, allow local users to change the ownership of arbitrary files via a symlink attack on (a) tomcat5-initd.log, (b) tomcat6-initd.log, (c) catalina.out, or (d) tomcat7-initd.log.
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Analysis
by VulDB Data Team • 05/20/2021
The vulnerability identified as CVE-2013-1976 represents a critical privilege escalation flaw affecting the init scripts of Apache Tomcat versions 5, 6, and 7 within specific enterprise distributions. This security weakness stems from improper handling of temporary files during the initialization process, creating a symlink attack vector that enables local attackers to manipulate file ownership. The affected systems include JBoss Enterprise Web Server versions 1.0.2 and 2.0.0, alongside Red Hat Enterprise Linux 5 and 6 distributions, making it particularly concerning for enterprise environments that rely on these platforms. The vulnerability operates through the creation of symbolic links that redirect the init scripts to target arbitrary files, allowing unauthorized users to gain elevated privileges by changing ownership of critical system files.
The technical implementation of this flaw involves the init scripts executing commands that create or modify log files without proper validation of file ownership or existence checks. Specifically, the scripts handle temporary files such as tomcat5-initd.log, tomcat6-initd.log, catalina.out, and tomcat7-initd.log, which are created in world-writable directories without adequate security controls. When these scripts run with elevated privileges during system startup or service management operations, they can be manipulated by local users who create symbolic links pointing to sensitive target files. This creates a race condition scenario where the init script performs operations on the symbolic link rather than the intended log file, ultimately resulting in the modification of file ownership to the attacking user's account.
The operational impact of CVE-2013-1976 extends beyond simple privilege escalation, as it provides attackers with persistent access to system resources and potential pathways for further compromise. Local users who exploit this vulnerability can manipulate critical log files, potentially corrupting system auditing mechanisms or redirecting log data to locations under their control. The attack surface is particularly dangerous in enterprise environments where multiple users may have local access to systems running these vulnerable Tomcat versions. Security researchers categorize this vulnerability under CWE-59, which addresses improper handling of symbolic links, and it aligns with ATT&CK technique T1068, focusing on exploiting local privilege escalation vulnerabilities. The presence of this flaw in widely deployed enterprise distributions means that organizations may be exposed to persistent threats without immediate awareness, as the vulnerability can be exploited silently during routine system operations.
Mitigation strategies for CVE-2013-1976 require immediate implementation of proper file handling procedures within the init scripts, including validation of file ownership and existence before file operations. System administrators should ensure that log files are created with appropriate permissions and that symbolic links are not allowed in directories used by init scripts. The recommended approach involves modifying the init scripts to use absolute paths for log files, implement proper file creation checks, and avoid world-writable directories for temporary file storage. Organizations should also consider upgrading to patched versions of the affected Tomcat distributions or implementing additional security controls such as file integrity monitoring systems. Regular security audits of init scripts and system configurations can help identify similar vulnerabilities, while adherence to security best practices such as principle of least privilege and secure file handling procedures can prevent exploitation of this and related vulnerabilities. The remediation process should include comprehensive testing to ensure that the fixes do not negatively impact legitimate system operations while effectively closing the security gap.