CVE-2019-5892 : Vulnerability Insights and Analysis

CVE-2019-5892 was published on January 10, 2019, and affects FRRouting FRR versions 2.x and 3.x before 3.0.4, 4.x before 4.0.1, 5.x before 5.0.2, and 6.x before 6.0.2. This vulnerability allows remote attackers to disrupt peering sessions by exploiting a specific attribute in BGP UPDATE packets.

Understanding CVE-2019-5892

CVE-2019-5892 is a vulnerability in FRRouting FRR that impacts various versions of the software, excluding Cumulus Linux or VyOS.

What is CVE-2019-5892?

The vulnerability arises when ENABLE_BGP_VNC is utilized for Virtual Network Control, enabling attackers to interfere with peering sessions by sending a BGP UPDATE packet with attribute 255. FRRouting's failure to comply with RFC 7606 leads to the rejection of packets containing attribute 255 as invalid VNC data, resulting in BGP session closure.

The Impact of CVE-2019-5892

This vulnerability allows remote attackers to disrupt BGP peering sessions, potentially causing denial of service by exploiting a specific attribute in BGP UPDATE packets.

Technical Details of CVE-2019-5892

CVE-2019-5892 involves the following technical aspects:

Vulnerability Description

The vulnerability in FRRouting FRR versions 2.x and 3.x before 3.0.4, 4.x before 4.0.1, 5.x before 5.0.2, and 6.x before 6.0.2 allows remote attackers to cause a denial of service by manipulating BGP UPDATE packets with attribute 255.

Affected Systems and Versions

FRRouting FRR versions 2.x and 3.x before 3.0.4
FRRouting FRR versions 4.x before 4.0.1
FRRouting FRR versions 5.x before 5.0.2
FRRouting FRR versions 6.x before 6.0.2

Exploitation Mechanism

The vulnerability is exploited by sending a BGP UPDATE packet with attribute 255, which triggers the disruption of peering sessions in affected FRRouting FRR versions.

Mitigation and Prevention

To address CVE-2019-5892, consider the following mitigation strategies:

Immediate Steps to Take

Apply the necessary patches provided by FRRouting for the affected versions.
Monitor network traffic for any suspicious activity related to BGP peering sessions.

Long-Term Security Practices

Regularly update FRRouting FRR to the latest versions to ensure security patches are in place.
Implement network segmentation and access controls to limit the impact of potential attacks.

Patching and Updates

Update FRRouting FRR to versions 3.0.4, 4.0.1, 5.0.2, and 6.0.2, which address the vulnerability and prevent exploitation.