CVE-2012-3421 in Performance Co-Pilot
Summary
by MITRE
The pduread function in pdu.c in libpcp in Performance Co-Pilot (PCP) before 3.6.5 does not properly time out connections, which allows remote attackers to cause a denial of service (pmcd hang) by sending individual bytes of a PDU separately, related to an "event-driven programming flaw."
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Analysis
by VulDB Data Team • 12/12/2021
The vulnerability identified as CVE-2012-3421 affects the Performance Co-Pilot (PCP) library component known as libpcp, specifically within the pduread function located in pdu.c. This flaw represents a significant security weakness that impacts the reliability and availability of systems relying on PCP for performance monitoring and data collection. The issue manifests in versions of PCP prior to 3.6.5, making it a long-standing concern that affected numerous production environments. The vulnerability stems from improper handling of connection timeouts, creating a condition where the system fails to properly manage the timing of data reception and processing.
The technical implementation of this vulnerability involves an event-driven programming flaw that directly impacts how the system processes Protocol Data Units (PDUs) received through network connections. When remote attackers exploit this weakness, they can deliberately fragment their PDU data by sending individual bytes separately over the network connection. This technique prevents the pduread function from properly recognizing complete PDUs, causing the system to wait indefinitely for additional data that may never arrive. The function's failure to implement proper timeout mechanisms means that pmcd, the Performance Co-Pilot collector daemon, becomes unresponsive and effectively hangs, unable to process further requests or maintain its monitoring functions.
The operational impact of this vulnerability extends beyond simple denial of service, creating a cascading effect that can severely disrupt system monitoring capabilities. When pmcd hangs due to this flaw, it cannot collect performance data from monitored systems, potentially leading to complete loss of visibility into system health and performance metrics. This situation is particularly concerning in enterprise environments where continuous monitoring is critical for operational stability and security incident response. The vulnerability allows attackers to maintain their disruptive influence without requiring authentication, making it an attractive target for malicious actors seeking to compromise system availability. The event-driven nature of the flaw means that the system remains vulnerable as long as the underlying programming logic is not corrected, regardless of network conditions or other mitigating factors.
This vulnerability aligns with CWE-400, which categorizes it as an "Uncontrolled Resource Consumption" or "Resource Exhaustion" issue, specifically manifesting as an improper timeout mechanism that allows attackers to exhaust system resources through connection management. The flaw also connects to ATT&CK technique T1499.004, which describes "Toggle Service State" and "Resource Exhaustion" tactics that can be employed to cause denial of service conditions. The root cause demonstrates poor input validation and connection handling practices that are common in event-driven systems where asynchronous processing creates complex state management challenges. Organizations should implement immediate mitigations including upgrading to PCP version 3.6.5 or later, where the timeout handling has been corrected to properly manage connection states and prevent indefinite waiting periods. Additional network-level protections such as connection timeouts and rate limiting can provide supplementary defense in depth measures against similar exploitation patterns.