CVE-2015-6282 in IOS XE
Summary
by MITRE
Cisco IOS XE 2.x and 3.x before 3.10.6S, 3.11.xS through 3.13.xS before 3.13.3S, and 3.14.xS through 3.15.xS before 3.15.1S allows remote attackers to cause a denial of service (device reload) via IPv4 packets that require NAT and MPLS actions, aka Bug ID CSCut96933.
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Analysis
by VulDB Data Team • 06/18/2022
Cisco IOS XE software versions 2.x and 3.x prior to specific patch releases contain a critical vulnerability that enables remote attackers to induce device reloads through carefully crafted IPv4 packets. This vulnerability specifically affects systems processing packets that require both Network Address Translation and Multiprotocol Label Switching operations, creating a condition where malformed or specially constructed packets can trigger system instability. The flaw resides in the packet processing engine's handling of these dual-operation scenarios, where the combination of NAT and MPLS processing creates a path for exploitation that ultimately results in device restarts. This vulnerability operates at the network layer and affects the core routing functionality of Cisco devices running the affected software versions, making it particularly dangerous in production environments where network availability is critical. The issue represents a classic denial of service vulnerability that can be exploited remotely without authentication, allowing attackers to disrupt network services and potentially cause cascading failures in connected systems.
The technical root cause of CVE-2015-6282 stems from insufficient input validation within the NAT and MPLS processing modules of Cisco IOS XE. When the system encounters IPv4 packets requiring both NAT and MPLS operations, the packet processing logic fails to properly handle certain edge cases in the packet structure or processing state. This validation gap creates a condition where an attacker can craft packets that, when processed by the device, cause memory corruption or state inconsistencies within the routing engine. The vulnerability is particularly insidious because it requires only a single packet to trigger the condition, making it highly effective for denial of service attacks. The flaw manifests when the device attempts to perform NAT operations on packets that also require MPLS processing, creating a race condition or buffer overflow scenario that leads to system instability and eventual device reload. This vulnerability aligns with CWE-129, Input Validation, and CWE-125, Out-of-bounds Read, as it involves improper handling of packet data during processing operations.
The operational impact of this vulnerability extends beyond simple service disruption, as device reloads can cause significant network downtime and potentially lead to more severe consequences in mission-critical environments. When affected devices experience reloads, they temporarily become unavailable for routing services, which can result in network partitions, service interruptions, and potential data loss during the restart process. Network administrators may experience challenges in troubleshooting and identifying the root cause of outages, particularly in large networks where multiple devices may be affected simultaneously. The vulnerability affects a wide range of Cisco IOS XE versions, requiring comprehensive vulnerability assessment across network infrastructure to identify affected devices. Organizations may need to implement temporary network segmentation or disable specific routing features to mitigate the risk while awaiting patches, which can impact overall network performance and functionality.
Mitigation strategies for CVE-2015-6282 should focus on immediate patch deployment and network monitoring to detect exploitation attempts. Cisco released patches for affected versions that address the packet processing logic and correct the input validation issues. Organizations should prioritize updating their Cisco IOS XE devices to versions 3.10.6S, 3.13.3S, or 3.15.1S, depending on their current software version. Network monitoring solutions should be configured to detect unusual packet patterns that may indicate exploitation attempts, particularly those involving NAT and MPLS processing. Implementing access control lists to filter suspicious packets or limiting NAT/MPLS processing on critical devices can provide temporary protection while patches are deployed. The vulnerability also highlights the importance of maintaining current security patches and conducting regular vulnerability assessments. From an ATT&CK framework perspective, this vulnerability maps to T1499.004, Endpoint Denial of Service, and T1566.002, Phishing via Service, as attackers may use this vulnerability to disrupt network services or as part of broader attack campaigns targeting network infrastructure. Security teams should implement network segmentation to limit the potential impact of successful exploitation and maintain detailed logs of network traffic for forensic analysis.