CVE-2019-1918 : Security Advisory and Response
Learn about CVE-2019-1918, a vulnerability in Cisco IOS XR Software that could lead to a denial of service situation. Find out the impact, affected systems, exploitation mechanism, and mitigation steps.
Cisco IOS XR Software Intermediate System–to–Intermediate System Denial of Service Vulnerability
Understanding CVE-2019-1918
This CVE involves a weakness in the implementation of the Intermediate System-to-Intermediate System (IS-IS) routing protocol functionality in Cisco IOS XR Software, potentially leading to a denial of service (DoS) situation.
What is CVE-2019-1918?
The vulnerability arises from incorrect handling of IS-IS link-state protocol data units (PDUs), allowing an unauthorized individual within the same IS-IS area to exploit the system.
The Impact of CVE-2019-1918
The vulnerability could result in a DoS condition by manipulating calculations in the weighted remote shared risk link groups (SRLG) or the IGP Flexible Algorithm, potentially causing system crashes or tracebacks.
Technical Details of CVE-2019-1918
Vulnerability Description
- Weakness in IS-IS routing protocol implementation in Cisco IOS XR Software
- Unauthorized exploitation within the same IS-IS area
Affected Systems and Versions
- Product: Cisco IOS XR Software
- Vendor: Cisco
- Versions: Unspecified
Exploitation Mechanism
- Attacker sends specific link-state PDUs to vulnerable systems
- Manipulates calculations in SRLG or IGP Flexible Algorithm
- May lead to system crashes or tracebacks
Mitigation and Prevention
Immediate Steps to Take
- Apply vendor patches and updates promptly
- Monitor network traffic for any suspicious activity
Long-Term Security Practices
- Regularly update and patch all software and firmware
- Implement network segmentation and access controls
Patching and Updates
- Refer to the vendor's security advisory for specific patch details