CVE-2003-0194 in tcpdump
Summary
by MITRE
tcpdump does not properly drop privileges to the pcap user when starting up.
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Analysis
by VulDB Data Team • 06/28/2021
The vulnerability identified as CVE-2003-0194 affects tcpdump, a widely used network packet analyzer and sniffer tool that operates on Unix-like systems. This issue stems from improper privilege management during the application's initialization phase, creating a significant security risk that can be exploited by malicious actors to gain elevated system access. The tcpdump utility is designed to capture and analyze network traffic, making it a critical tool for network administrators and security professionals. However, when tcpdump starts up, it fails to correctly transition from root privileges to a less privileged pcap user account, leaving the process running with elevated permissions unnecessarily.
The technical flaw manifests in tcpdump's privilege dropping mechanism, which is a fundamental security feature designed to minimize the potential damage from security vulnerabilities by running applications with the least privilege necessary. According to the Common Weakness Enumeration standard CWE-279, this represents an improper privilege management issue where the software does not correctly enforce privilege separation. The vulnerability occurs because tcpdump does not properly execute the setuid/setgid operations required to drop root privileges, allowing the process to maintain elevated permissions throughout its execution cycle. This behavior creates an attack surface where any exploit targeting tcpdump could potentially leverage these elevated privileges to perform actions that would otherwise be restricted.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it fundamentally undermines the security model of the tcpdump utility and potentially affects the broader network infrastructure. When tcpdump runs with root privileges, it can access all network interfaces and potentially read all network traffic on the system, regardless of user permissions. This creates a significant risk for network administrators who rely on tcpdump for legitimate monitoring purposes, as the tool becomes a potential vector for privilege escalation attacks. According to MITRE ATT&CK framework, this vulnerability maps to privilege escalation techniques where adversaries exploit improper privilege management to gain elevated access. The impact is particularly severe in multi-tenant environments or systems where tcpdump is frequently used with root privileges, as it provides a consistent attack vector for malicious actors to compromise system integrity.
The mitigation strategy for CVE-2003-0194 requires immediate attention from system administrators and security teams. The most effective approach involves ensuring that tcpdump is properly configured to drop privileges upon startup by verifying the correct ownership and permissions of the tcpdump binary, typically setting the setuid bit to the pcap user account. System administrators should also implement regular privilege auditing procedures to identify any processes running with unnecessary elevated privileges. Additional mitigations include restricting tcpdump's execution to trusted users only, implementing proper network segmentation to limit access to systems running tcpdump, and ensuring that the pcap user account has minimal required permissions. The vulnerability highlights the importance of proper privilege management in security-critical applications and serves as a reminder of the need for regular security audits to identify and address similar privilege escalation issues. Organizations should also consider implementing monitoring solutions to detect unauthorized privilege escalation attempts and maintain updated security patches to prevent exploitation of known vulnerabilities.