CVE-2015-4204 in IOS
Summary
by MITRE
Memory leak in Cisco IOS 12.2 in the Performance Routing Engine (PRE) module on uBR10000 devices allows remote authenticated users to cause a denial of service (memory consumption or PXF process crash) by sending docsIfMCmtsMib SNMP requests quickly, aka Bug ID CSCue65051.
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Analysis
by VulDB Data Team • 05/21/2022
The vulnerability identified as CVE-2015-4204 represents a critical memory management flaw within Cisco IOS 12.2 operating on uBR10000 series devices. This issue specifically affects the Performance Routing Engine (PRE) module, which serves as a crucial component for handling routing and performance monitoring functions within broadband access networks. The vulnerability manifests as a memory leak that occurs during the processing of SNMP requests, particularly those related to the docsIfMCmtsMib object identifier. The flaw impacts network infrastructure devices that are widely deployed in service provider environments, where continuous uptime and reliable performance are paramount for maintaining service availability.
The technical exploitation of this vulnerability occurs through the manipulation of SNMP communication protocols within the PRE module. When authenticated remote attackers send rapid sequences of docsIfMCmtsMib SNMP requests to affected uBR10000 devices, the system fails to properly release allocated memory resources during request processing. This memory leak progressively consumes available system memory, leading to either sustained memory exhaustion or complete crash of the PXF (Performance eXtension Framework) process responsible for performance monitoring functions. The vulnerability is particularly concerning because it requires only authenticated access to exploit, meaning that legitimate users with appropriate credentials can trigger the denial of service condition. The flaw demonstrates poor memory management practices within the SNMP processing subsystem and represents a failure in resource cleanup operations that should be handled automatically by the operating system.
The operational impact of CVE-2015-4204 extends beyond simple service disruption to potentially compromise entire network segments managed by affected devices. When the PXF process crashes or memory consumption reaches critical levels, the device loses its ability to perform performance monitoring and routing functions effectively. This can result in degraded service quality, incomplete performance data collection, and potential routing instability that affects downstream network services. Network administrators may experience difficulties in troubleshooting performance issues as the monitoring capabilities become unavailable, while customers may experience intermittent connectivity problems or service interruptions. The vulnerability particularly affects service provider networks where uBR10000 devices serve as core infrastructure elements managing large numbers of customer connections, making the impact of such denial of service conditions significant for business continuity.
Cisco has addressed this vulnerability through software updates and patches that improve memory management within the PRE module's SNMP processing capabilities. The fix involves implementing proper memory deallocation procedures and adding additional safeguards to prevent memory leaks during SNMP request processing. Organizations should prioritize applying the relevant security patches to their Cisco IOS 12.2 systems, particularly those running on uBR10000 devices. Network security monitoring should include detection of unusual SNMP traffic patterns that might indicate exploitation attempts, and administrators should implement access controls to limit SNMP access to trusted management systems only. The vulnerability aligns with CWE-401, which addresses improper release of memory, and represents a classic example of how insufficient resource management can lead to denial of service conditions that affect critical network infrastructure. This vulnerability also maps to ATT&CK technique T1499.004, which covers network disruption through resource exhaustion, highlighting the strategic importance of addressing such memory management flaws in enterprise network security posture.