CVE-2019-1809 : Exploit Details and Defense Strategies

A flaw in the Image Signature Verification feature of Cisco NX-OS Software allows a local attacker with administrator-level credentials to install a harmful software patch on a vulnerable device by evading digital signature checks.

Understanding CVE-2019-1809

What is CVE-2019-1809?

The vulnerability in Cisco NX-OS Software enables an attacker to load a malicious software patch on a device by bypassing signature verification.

The Impact of CVE-2019-1809

The vulnerability has a CVSS base score of 6.4, indicating a medium severity issue with high impacts on confidentiality, integrity, and availability.

Technical Details of CVE-2019-1809

Vulnerability Description

Inadequate verification of digital signatures for patch images in Cisco NX-OS Software
Allows a local attacker to install harmful software patches

Affected Systems and Versions

Product: Cisco NX-OS Software
Versions affected: Less than 8.3(1)

Exploitation Mechanism

Attacker creates an unsigned software patch to evade signature checks
Loads the patch onto the device and initiates booting of a malicious software patch image

Mitigation and Prevention

Immediate Steps to Take

Apply vendor-provided patches or updates promptly
Monitor Cisco's security advisories for any new information

Long-Term Security Practices

Implement the principle of least privilege for user accounts
Regularly review and update security policies and procedures

Patching and Updates

Regularly check for and apply security patches and updates provided by Cisco