CVE-2016-9203 in ASR 5000
Summary
by MITRE
A vulnerability in the Internet Key Exchange Version 2 (IKEv2) feature of Cisco ASR 5000 Series Software could allow an unauthenticated, remote attacker to cause a reload of the ipsecmgr process. More Information: CSCvb38398. Known Affected Releases: 20.2.3 20.2.3.65026. Known Fixed Releases: 21.1.M0.65431 21.1.PP0.65733 21.1.R0.65467 21.1.R0.65496 21.1.VC0.65434 21.1.VC0.65489 21.2.A0.65437.
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Analysis
by VulDB Data Team • 10/05/2022
The vulnerability identified as CVE-2016-9203 resides within the Internet Key Exchange Version 2 implementation of Cisco ASR 5000 Series Software, representing a critical weakness that enables unauthenticated remote attackers to disrupt service availability. This issue specifically targets the ipsecmgr process, which serves as a fundamental component in managing IPsec security associations and key exchanges within the router infrastructure. The vulnerability stems from inadequate input validation mechanisms within the IKEv2 protocol handling code, allowing malicious actors to craft specially crafted packets that trigger unexpected behavior in the affected system's processing logic.
The technical flaw manifests through improper handling of malformed IKEv2 messages during the negotiation phase, where the system fails to properly validate incoming packet structures before processing them. This validation gap creates an exploitable condition that can be leveraged by remote attackers without requiring any authentication credentials, making the vulnerability particularly dangerous in publicly accessible network environments. The specific nature of the flaw allows an attacker to send crafted IKEv2 packets that cause the ipsecmgr process to terminate unexpectedly, resulting in an automatic system reload that disrupts ongoing network operations and potentially creates service outages.
From an operational impact perspective, this vulnerability poses significant risks to network infrastructure reliability and availability, particularly in enterprise and service provider environments where the ASR 5000 series routers serve as critical routing and security devices. The automatic reload of the ipsecmgr process can lead to temporary loss of IPsec connectivity, requiring network administrators to manually intervene and restore services. The vulnerability's remote exploitability means that attackers can potentially cause denial of service conditions without physical access to the network equipment, making it a particularly attractive target for malicious actors seeking to disrupt network operations. This issue directly aligns with CWE-121, which addresses heap-based buffer overflow conditions, and may also relate to CWE-122, concerning buffer overflow conditions, as the improper input validation likely creates conditions where buffer boundaries are exceeded.
The attack surface for this vulnerability extends across all network environments utilizing affected Cisco ASR 5000 Series software versions, particularly those implementing IPsec VPN services or relying on IKEv2 for secure communications. Network security frameworks such as NIST SP 800-53 and ISO 27001 would classify this as a high-severity vulnerability requiring immediate remediation, as it directly impacts the availability and integrity of network security services. Organizations implementing the affected software versions should consider this vulnerability as part of their comprehensive risk assessment, particularly when evaluating their network security postures and incident response capabilities. The vulnerability's exploitation can result in cascading effects throughout the network infrastructure, as IPsec services are often critical for secure inter-domain communications and remote access services.
Mitigation strategies should prioritize immediate software updates to the fixed releases indicated in the vulnerability advisory, specifically versions 21.1.M0.65431 through 21.2.A0.65437, which contain the necessary code modifications to address the input validation issues. Network administrators should also implement additional monitoring controls to detect anomalous IKEv2 traffic patterns that might indicate exploitation attempts, utilizing intrusion detection systems and network traffic analysis tools. The remediation process should include comprehensive testing of the updated software in controlled environments before deployment to production networks to ensure that the patch does not introduce compatibility issues with existing network configurations. Organizations should also consider implementing network segmentation strategies to limit the potential impact of exploitation attempts and establish clear incident response procedures that address potential service disruptions caused by this vulnerability.