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An updated xinetd package that fixes one security issue and two bugs is now available for Red Hat Enterprise Linux 6.
The Red Hat Security Response Team has rated this update as having low security impact. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) associated with each description below.
The xinetd package provides a secure replacement for inetd, the Internet services daemon. xinetd provides access control for all services based on the address of the remote host and/or on time of access, and can prevent denial-of-access attacks.
- When xinetd services are configured with the "TCPMUX" or "TCPMUXPLUS" type, and the tcpmux-server service is enabled, those services are accessible via port 1. It was found that enabling the tcpmux-server service (it is disabled by default) allowed every xinetd service, including those that are not configured with the "TCPMUX" or "TCPMUXPLUS" type, to be accessible via port 1. This could allow a remote attacker to bypass intended firewall restrictions.
Red Hat would like to thank Thomas Swan of FedEx for reporting this issue.
- Prior to this update, a file descriptor array in the service.c source file was not handled as expected. As a consequence, some of the descriptors remained open when xinetd was under heavy load. Additionally, the system log was filled with a large number of messages that took up a lot of disk space over time. This update modifies the xinetd code to handle the file descriptors correctly and messages no longer fill the system log.
- Prior to this update, services were disabled permanently when their CPS limit was reached. As a consequence, a failed bind operation could occur when xinetd attempted to restart the service. This update adds additional logic that attempts to restart the service. Now, the service is only disabled if xinetd cannot restart the service after 30 attempts.
All users of xinetd are advised to upgrade to this updated package, which contains backported patches to correct these issues.