CVE-2016-9216 in ASR 5000
Summary
by MITRE
An IKE Packet Parsing Denial of Service Vulnerability in the ipsecmgr process of Cisco ASR 5000 Software could allow an unauthenticated, remote attacker to cause the ipsecmgr process to reload. More Information: CSCuy06917 CSCuy45036 CSCuy59525. Known Affected Releases: 20.0.0 20.0.M0.62842 20.0.v0 20.0.M0.63229 20.1.0 20.1.a0 20.1.v0 21.0.0 21.0.v0. Known Fixed Releases: 20.0.0 20.0.0.63250 20.0.M0.63148 20.0.R0.63294 20.0.R0.63316 20.0.V0.63170 20.0.VG0.63188 20.0.v0 20.0.v0.64175 20.0.vg0.63522 20.1.A0.63166 20.2.A0.63174 20.1.A0.63232 20.2.A0.63237 20.0.M0.63226 20.0.M0.63229 20.0.R0.63294 20.0.R0.63316 20.0.V0.63263 20.0.VG0.63233 20.0.v0 20.0.v0.64175 20.0.vg0.63522 20.1.0 20.1.0.63959 20.1.M0.63876 20.1.T0.63886 20.1.V0.64231 20.1.VA0.64194 20.1.VB0.64210 20.1.a0 20.1.a0.64023 20.1.v0 20.1.v0.64607 20.2.A0.63895 21.0.0 21.0.0.65256 21.0.M0.63881 21.0.M0.64281 21.0.PP0.64366 21.0.V0.65052 21.0.v0 21.0.v0.65831 21.0.vb0.65887 21.1.R0.65130 21.1.R0.65135.
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Analysis
by VulDB Data Team • 05/14/2026
The CVE-2016-9216 vulnerability represents a critical denial of service flaw within the ipsecmgr process of Cisco ASR 5000 Series Software, specifically targeting the Internet Key Exchange (IKE) packet parsing functionality. This vulnerability resides in the core security infrastructure of network devices, making it particularly dangerous as it can be exploited by authenticated remote attackers to disrupt critical network services. The issue affects multiple software releases including versions 20.0.x, 20.1.x, and 21.0.x, indicating a widespread impact across the product line. The vulnerability manifests when the ipsecmgr process encounters malformed or specially crafted IKE packets, leading to process instability and subsequent reload operations that can disrupt network connectivity and security services.
The technical nature of this vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions, and CWE-122, which covers buffer overflow vulnerabilities in heap-based memory. The flaw occurs during the parsing of IKE packets within the ipsecmgr component, where insufficient input validation and boundary checking allows an attacker to craft malicious packets that trigger memory corruption. This type of vulnerability is particularly concerning in network infrastructure devices as it can be exploited to create persistent denial of service conditions that may require manual intervention to resolve. The vulnerability's classification under the ATT&CK framework would fall under T1499.004 for Network Denial of Service, specifically targeting network infrastructure components.
The operational impact of this vulnerability extends beyond simple service disruption, as the ipsecmgr process is fundamental to IPsec security operations within the ASR 5000 platform. When the process reloads due to exploitation, it can cause temporary loss of IPsec tunnel functionality, potentially exposing network segments to unauthorized access while the system reestablishes security services. The vulnerability affects organizations that rely on IPsec for secure communications, VPN services, and network segmentation, making it a significant concern for enterprise and service provider networks. Recovery from such an attack requires either manual system intervention or automatic restart mechanisms that can take several minutes to complete, resulting in service degradation and potential security gaps during the reload process.
Mitigation strategies for CVE-2016-9216 should prioritize immediate deployment of vendor-provided patches and updates from Cisco, specifically targeting the fixed releases listed in the advisory. Network administrators should implement network segmentation and access controls to limit the attack surface, ensuring that only authorized personnel can access the affected system interfaces. Monitoring for unusual packet patterns and implementing intrusion detection systems can help identify exploitation attempts before they succeed. Additionally, organizations should maintain comprehensive backup and recovery procedures for their network infrastructure, as the process reload can potentially leave systems in an inconsistent state. Regular security assessments and vulnerability scanning should be conducted to identify similar issues in other network components, while implementing network access controls and authentication mechanisms to reduce the risk of unauthorized access to the vulnerable system. The fix addresses the root cause by implementing proper input validation and boundary checking within the IKE packet parsing logic, preventing the memory corruption that leads to process reloads.