CVE-2019-15998 : Security Advisory and Response

A vulnerability in Cisco IOS XR Software allows connections despite a configured access control list (ACL) that denies access to NETCONF over SSH. This issue arises from a lack of a check in the NETCONF over SSH ACL.

Understanding CVE-2019-15998

This CVE involves a security vulnerability in Cisco IOS XR Software that could potentially allow unauthorized access to affected devices.

What is CVE-2019-15998?

The vulnerability enables attackers to connect to affected devices using NETCONF over SSH, bypassing ACL restrictions. Successful exploitation grants access to the device on the NETCONF port, requiring valid credentials for further access.

The Impact of CVE-2019-15998

The vulnerability poses a medium severity risk with a CVSS base score of 5.3. However, there have been no reported public exploits or malicious activities related to this issue.

Technical Details of CVE-2019-15998

This section delves into the specifics of the vulnerability.

Vulnerability Description

The flaw allows unauthorized connections to Cisco IOS XR Software devices despite ACL restrictions on NETCONF over SSH due to a missing check in the ACL.

Affected Systems and Versions

Product: Cisco IOS XR Software
Vendor: Cisco
Versions: Unspecified

Exploitation Mechanism

Attack Complexity: Low
Attack Vector: Network
Privileges Required: None
User Interaction: None
Integrity Impact: Low
Confidentiality Impact: None
Scope: Unchanged
Vector String: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Base Score: 5.3 (Medium Severity)

Mitigation and Prevention

Protecting systems from this vulnerability requires immediate actions and long-term security practices.

Immediate Steps to Take

Monitor vendor updates and security advisories regularly.
Implement ACLs and firewall rules to restrict unauthorized access.
Ensure strong, unique credentials for device access.

Long-Term Security Practices

Conduct regular security audits and vulnerability assessments.
Train staff on best security practices and incident response procedures.

Patching and Updates

Apply patches and updates provided by Cisco to address this vulnerability.