CVE-2015-1465 in Android
Summary
by MITRE • 01/26/2023
The IPv4 implementation in the Linux kernel before 3.18.8 does not properly consider the length of the Read-Copy Update (RCU) grace period for redirecting lookups in the absence of caching, which allows remote attackers to cause a denial of service (memory consumption or system crash) via a flood of packets.
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Analysis
by VulDB Data Team • 01/26/2023
The vulnerability described in CVE-2015-1465 represents a critical flaw in the Linux kernel's IPv4 implementation that affects versions prior to 3.18.8. This issue stems from improper handling of Read-Copy Update (RCU) grace periods during redirect lookups when caching mechanisms are absent. The vulnerability specifically targets the kernel's network stack implementation, creating a scenario where remote attackers can exploit the system's memory management and lookup processes to cause significant operational disruption. The flaw manifests when the kernel fails to properly account for the duration of RCU grace periods during packet processing, leading to potential memory exhaustion or system instability.
The technical implementation of this vulnerability involves the kernel's approach to handling network packet redirects without cache utilization. When network packets arrive and require lookup redirection, the kernel's RCU mechanism should properly manage the grace period required for safe memory updates. However, in affected versions, the implementation does not adequately consider the time constraints of these grace periods, particularly when no caching is available to optimize the lookup process. This oversight creates a condition where malicious actors can flood the system with specially crafted packets that trigger repeated lookup operations, causing the kernel to consume excessive memory resources or potentially crash the entire system.
From an operational perspective, this vulnerability presents a significant risk to network infrastructure and server availability. The denial of service attack can be executed remotely without requiring authentication or elevated privileges, making it particularly dangerous for systems exposed to untrusted network traffic. Attackers can consume system resources through memory exhaustion attacks or cause system crashes by exploiting the improper RCU grace period handling. The impact extends beyond simple service disruption as the vulnerability affects core kernel functionality that underpins network communications, potentially compromising entire network services and applications that depend on stable kernel operation.
The vulnerability aligns with CWE-122, which describes improper restriction of operations within a limited error handling context, and represents a classic case of resource exhaustion through improper state management. From an ATT&CK framework perspective, this vulnerability maps to T1499.004, which covers network denial of service, and T1566.001, covering spearphishing via social engineering, though the latter is more relevant for initial access rather than the specific exploitation mechanism. The attack vector primarily involves network packet flooding that exploits the kernel's memory management and lookup mechanisms, making it particularly dangerous for network servers, routers, and systems handling high volumes of traffic. Organizations should implement immediate mitigations including kernel updates to versions 3.18.8 or later, network segmentation to limit exposure, and monitoring for unusual packet patterns that may indicate exploitation attempts.
The broader implications of this vulnerability extend to system reliability and availability for organizations relying on Linux-based network infrastructure. The flaw demonstrates the critical importance of proper synchronization mechanisms in kernel-level code, particularly when dealing with concurrent access patterns and memory management operations. The vulnerability's exploitation requires minimal privileges and can be executed at scale, making it an attractive target for both opportunistic attackers and organized threat groups seeking to disrupt network services. Security teams must prioritize patch management for this vulnerability while also implementing network monitoring to detect potential exploitation attempts through abnormal traffic patterns or memory consumption spikes that indicate successful exploitation of the RCU grace period handling flaw.