Overview
CVE-2025-8870 is a security vulnerability affecting certain platforms running Arista EOS (Extensible Operating System). This vulnerability allows a malicious actor with access to the device’s serial console to trigger an unexpected device reload by providing specially crafted input. This can lead to denial-of-service (DoS) conditions.
Technical Details
The vulnerability stems from improper handling of specific input sequences received through the serial console interface. Under certain circumstances, this malformed input can cause a critical error within the EOS operating system, resulting in a device reload. The exact nature of the vulnerable code segment is not publicly disclosed in detail, however the core issue involves the device’s inability to correctly process particular console commands, ultimately leading to system instability. Understanding the specific console commands which can cause the issue is critical when developing the proof of concept.
CVSS Analysis
- CVSS Score: 4.9 (Medium)
- This score reflects the need for physical or local access to the serial console, which reduces the overall exploitability compared to remote vulnerabilities. While a reload can cause significant disruptions, the necessary prerequisites limit the scope of the vulnerability.
Possible Impact
A successful exploit of CVE-2025-8870 can lead to:
- Denial of Service (DoS): The affected Arista EOS device will unexpectedly reload, interrupting network traffic and potentially impacting critical services.
- Network Instability: Repeated reloads can cause significant network instability and performance degradation.
Mitigation and Patch Steps
Arista has released a security advisory addressing this vulnerability. The following steps are recommended to mitigate the risk:
- Apply the Latest EOS Software Update: Upgrade to the latest stable release of Arista EOS that includes the fix for CVE-2025-8870. Refer to the Arista security advisory for specific affected versions and fixed versions.
- Restrict Serial Console Access: Implement strict access controls to the serial console interface. Limit access to authorized personnel only.
- Monitor Serial Console Activity: Implement logging and monitoring of serial console activity to detect any suspicious or malicious commands.
- Consider physical security: Restrict unauthorized physical access to the devices.
