CVE-2017-12319 is classified as a medium-severity vulnerability affecting Cisco IOS XE Software. This vulnerability allows an unauthenticated, remote attacker to potentially cause the device to reload, resulting in a denial of service (DoS) condition. Additionally, it could corrupt the BGP routing table, leading to network instability. The significance of this vulnerability lies in its potential impact on network operations, particularly for organizations relying on Cisco devices for their routing infrastructure.
The vulnerability exists due to changes in the implementation of the BGP MPLS-Based Ethernet VPN RFC (RFC 7432) draft between IOS XE software releases. If the device is not configured for EVPN, it is not vulnerable. Organizations should prioritize patching immediately to mitigate the risks associated with this vulnerability.
As of now, there is no public exploit confirmed for this vulnerability, but it is essential for organizations to remain vigilant and ensure their systems are updated. The vulnerability was added to the Known Exploited Vulnerabilities (KEV) catalog on March 3, 2022, indicating its relevance in the cybersecurity landscape.
Organizations should assess their network infrastructure for affected Cisco devices and take immediate action to apply the recommended patches provided by Cisco.
Vulnerability Details
A vulnerability in the Border Gateway Protocol (BGP) over an Ethernet Virtual Private Network (EVPN) for Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause the device to reload, resulting in a denial of service (DoS) condition, or potentially corrupt the BGP routing table, which could result in network instability. This vulnerability affects all releases of Cisco IOS XE Software prior to software release 16.3 that support BGP EVPN configurations. If the device is not configured for EVPN, it is not vulnerable.
The CVSS score for this vulnerability is 5.9, indicating a medium severity level. The vulnerability has been tracked under Cisco Bug IDs: CSCui67191, CSCvg52875.
Technical Analysis
The root cause of this vulnerability stems from changes made to the BGP implementation in IOS XE Software. Specifically, when the BGP Inclusive Multicast Ethernet Tag Route or BGP EVPN MAC/IP Advertisement Route update packet is received, the IP address length field may be miscalculated, allowing an attacker to exploit this vulnerability by sending a crafted BGP packet to an affected device after the BGP session has been established.
The attack vector is over the network, and the attack complexity is classified as high, meaning that the attacker must have specific knowledge about the target and its BGP configurations. No privileges are required to exploit this vulnerability, and user interaction is not necessary.
The impact on availability is high, as the device may reload or the BGP routing table may become corrupted, leading to a DoS condition. There are no impacts on confidentiality or integrity.
Risk & Impact Analysis
Risk to organizations includes potential network downtime and instability due to the possibility of a denial of service caused by this vulnerability. Given that this vulnerability affects Cisco's IOS XE Software used in critical network infrastructure, the potential blast radius is significant, impacting organizations' operations and service delivery.
Organizations should address this vulnerability in their priority patch cycle due to its inclusion in the KEV catalog and its implications for network stability.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | Yes |
Ransomware Use | No |
Affected Versions
This vulnerability affects all releases of Cisco IOS XE Software prior to software release 16.3 that support BGP EVPN configurations. Organizations should ensure that they are running an updated version of the software to mitigate this vulnerability.
Mitigation & Remediation
Organizations should apply updates as per vendor instructions to remediate this vulnerability. For detailed guidance, refer to the vendor's advisory, such as the one provided by Cisco at Cisco's Security Advisory. Additionally, organizations should consider implementing network controls to limit exposure to potential exploitation attempts.
Detection Guidance
To detect potential exploit attempts, organizations should monitor logs for unusual BGP routing messages and look for behavioral anomalies that may indicate an attempted exploitation of this vulnerability. Ensuring that network monitoring systems are in place can help identify such activities in real-time.
AppSecure Threat Intelligence Insight
The long-term significance of CVE-2017-12319 highlights the ongoing challenges with BGP implementations and their impact on network stability. This vulnerability represents a broader trend of vulnerabilities in network protocols that can be exploited remotely, emphasizing the need for rigorous security assessments.
Security teams should take lessons from this incident to strengthen their defenses against similar vulnerabilities. Strategies may include conducting regular vulnerability assessments and incorporating penetration testing as part of their security practices.
In conclusion, organizations should prioritize their remediation efforts and stay informed about the evolving threat landscape to protect their network infrastructure effectively.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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