CVE-2010-3697 in FreeRADIUS
Summary
by MITRE
The wait_for_child_to_die function in main/event.c in FreeRADIUS 2.1.x before 2.1.10, in certain circumstances involving long-term database outages, does not properly handle long queue times for requests, which allows remote attackers to cause a denial of service (daemon crash) by sending many requests.
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Analysis
by VulDB Data Team • 09/26/2021
The vulnerability described in CVE-2010-3697 affects the FreeRADIUS server software version 2.1.x prior to 2.1.10, specifically within the main/event.c file where the wait_for_child_to_die function operates. This flaw represents a classic denial of service condition that exploits improper handling of request queue times during extended database connectivity issues. The vulnerability manifests when the system encounters prolonged database outages, creating a scenario where the daemon becomes unresponsive to legitimate requests.
The technical implementation of this vulnerability stems from inadequate error handling within the wait_for_child_to_die function, which fails to properly manage the timing of request processing when database connections are unavailable for extended periods. When multiple requests are submitted during these database outage conditions, the function does not correctly manage the queue timeouts, leading to a cascade of failures that ultimately causes the FreeRADIUS daemon to crash. This behavior aligns with CWE-400 vulnerability classification related to resource exhaustion and improper handling of exceptional conditions.
From an operational perspective, this vulnerability presents significant risk to network infrastructure relying on FreeRADIUS for authentication services. Remote attackers can exploit this weakness by crafting and sending numerous requests to the vulnerable server, triggering the daemon crash condition without requiring authentication or specialized privileges. The impact extends beyond simple service disruption as it can affect network access control, potentially compromising network security posture and user authentication capabilities.
The attack pattern associated with this vulnerability follows the ATT&CK technique T1499.004 for Network Denial of Service, where adversaries leverage software flaws to disrupt network services. The vulnerability demonstrates how database connectivity issues can be weaponized to cause service disruption through request flooding, making it particularly dangerous in environments where authentication services are critical for network operations.
Mitigation strategies for this vulnerability include immediate deployment of FreeRADIUS version 2.1.10 or later, which contains the patched implementation of the wait_for_child_to_die function. Organizations should also implement proper monitoring and alerting for database connectivity issues to proactively address potential conditions that could trigger the vulnerability. Additionally, network segmentation and rate limiting mechanisms can help reduce the impact of potential exploitation attempts while the primary patch is being deployed. The fix addresses the underlying resource management issue by implementing proper timeout handling and queue management that prevents the daemon from crashing under sustained load during database outage conditions.