CVE-2013-4342 in Red Hat
Summary
by MITRE
xinetd does not enforce the user and group configuration directives for TCPMUX services, which causes these services to be run as root and makes it easier for remote attackers to gain privileges by leveraging another vulnerability in a service.
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Analysis
by VulDB Data Team • 01/08/2022
The vulnerability identified as CVE-2013-4342 affects the xinetd daemon, a widely used super-server that manages internet services and provides a centralized mechanism for handling incoming network connections. This issue specifically pertains to TCPMUX services which are designed to multiplex multiple services over a single port. The fundamental flaw lies in xinetd's failure to properly enforce user and group configuration directives when executing TCPMUX services, creating a critical security gap that undermines the principle of least privilege.
The technical implementation of this vulnerability stems from xinetd's handling of service configuration files where the user and group directives are explicitly defined to specify which user context services should run under. However, for TCPMUX services, the daemon bypasses these security controls entirely, causing services to execute with root privileges regardless of the configured user directive. This behavior represents a direct violation of security best practices and creates a dangerous attack surface where remote exploitation can occur through other service vulnerabilities that may exist within the TCPMUX framework.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it fundamentally compromises the security model of systems relying on xinetd for service management. Attackers can leverage this weakness by first identifying other vulnerabilities present in TCPMUX services and then exploiting the fact that these services run with root privileges. This creates a scenario where a single vulnerability can be exploited to gain full system control, as demonstrated by various attack vectors that have been documented in security research. The vulnerability is particularly dangerous because it affects the core service management functionality rather than individual applications, making it a systemic security issue.
From a cybersecurity perspective, this vulnerability aligns with CWE-276, which addresses improper privileges, and represents a classic case of privilege escalation through service misconfiguration. The ATT&CK framework categorizes this as a privilege escalation technique where adversaries manipulate service configurations to gain elevated access. The vulnerability also relates to CWE-787, concerning out-of-bounds writes, as the improper handling of user directives can lead to unexpected behavior in service execution contexts. Organizations should implement immediate mitigations including disabling TCPMUX services when not required, properly configuring user directives for all services, and conducting comprehensive security audits of service configurations. Regular monitoring for unauthorized service modifications and implementing automated configuration management systems can help prevent exploitation of this vulnerability. The recommended remediation involves upgrading to patched versions of xinetd or implementing alternative service management approaches that properly enforce privilege separation for all service types.