CVE-2011-1159 in acpid
Summary
by MITRE
acpid.c in acpid before 2.0.9 does not properly handle a situation in which a process has connected to acpid.socket but is not reading any data, which allows local users to cause a denial of service (daemon hang) via a crafted application that performs a connect system call but no read system calls.
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Analysis
by VulDB Data Team • 01/15/2025
The vulnerability described in CVE-2011-1159 affects the acpid daemon version 2.0.8 and earlier, specifically within the acpid.c component responsible for handling ACPI (Advanced Configuration and Power Interface) events. This flaw represents a classic resource exhaustion issue that can be exploited to cause a daemon hang, effectively leading to a denial of service condition. The acpid daemon serves as a crucial interface between the operating system and hardware power management features, making it a critical component for system stability and power control operations.
The technical flaw stems from improper handling of socket connections within the acpid daemon's event processing loop. When a process establishes a connection to the acpid.socket but fails to read data from it, the daemon enters a problematic state where it waits indefinitely for data that will never arrive. This occurs because the daemon's socket handling logic does not implement proper timeouts or connection monitoring mechanisms to detect and terminate idle connections. The vulnerability specifically exploits the absence of read operations after connection establishment, creating a scenario where the daemon's event processing becomes blocked and unresponsive to legitimate ACPI events.
From an operational impact perspective, this vulnerability allows local attackers to disrupt system power management functionality by creating multiple stale connections to the acpid daemon. The daemon hang prevents it from processing actual ACPI events such as battery status changes, thermal events, or power button presses, potentially leading to system instability, unexpected shutdowns, or failure to respond to critical power management signals. This issue affects systems where acpid is actively managing hardware power states and can result in reduced system reliability and user experience degradation.
The vulnerability aligns with CWE-400, which addresses "Uncontrolled Resource Consumption," and demonstrates characteristics consistent with resource exhaustion attacks that target daemon processes. From an ATT&CK framework perspective, this vulnerability maps to T1499.004, "Endpoint Denial of Service," as it enables adversaries to consume system resources and cause service unavailability. The local privilege requirement makes this attack vector particularly concerning for systems where unprivileged users have access to execute applications that can connect to system services. Mitigation strategies should include updating to acpid version 2.0.9 or later, implementing connection timeouts, and monitoring for abnormal connection patterns to prevent exploitation of this vulnerability.
The root cause of this vulnerability highlights the importance of proper socket management and resource cleanup in daemon implementations. Modern security practices emphasize implementing robust timeout mechanisms and connection monitoring to prevent resource exhaustion attacks. System administrators should also consider implementing process monitoring and alerting for unusual connection patterns to detect potential exploitation attempts. This vulnerability demonstrates how seemingly minor implementation flaws in system daemons can have significant operational impacts on power management and overall system stability, reinforcing the need for comprehensive security testing of critical system components.