CVE-2018-5381 Explained : Impact and Mitigation

A bug has been identified in the parsing of "Capabilities" in BGP OPEN messages in the Quagga BGP daemon (bgpd), specifically in the bgp_packet.c:bgp_capability_msg_parse function. This bug occurs in versions prior to 1.2.3. If an unrecognized AFI/SAFI is present in a Multi-Protocol capability, the parser may enter an infinite loop, resulting in a denial of service.

Understanding CVE-2018-5381

What is CVE-2018-5381?

The CVE-2018-5381 vulnerability is found in the Quagga BGP daemon (bgpd) before version 1.2.3 due to a bug in parsing "Capabilities" in BGP OPEN messages.

The Impact of CVE-2018-5381

The vulnerability has a CVSS base score of 6.5, with a medium severity rating. It can lead to a denial of service due to an infinite loop caused by an unrecognized AFI/SAFI in a Multi-Protocol capability.

Technical Details of CVE-2018-5381

Vulnerability Description

The bug in the bgp_packet.c:bgp_capability_msg_parse function of Quagga bgpd versions prior to 1.2.3 allows for a denial of service attack through an infinite loop triggered by an unrecognized AFI/SAFI.

Affected Systems and Versions

Product: bgpd
Vendor: Quagga
Versions Affected: < 1.2.3

Exploitation Mechanism

The vulnerability can be exploited by sending BGP OPEN messages with an unrecognized AFI/SAFI in the Multi-Protocol capability, causing the parser to enter an infinite loop.

Mitigation and Prevention

Immediate Steps to Take

Update Quagga bgpd to version 1.2.3 or later to mitigate the vulnerability.
Monitor network traffic for any suspicious BGP OPEN messages.

Long-Term Security Practices

Regularly update and patch software to prevent known vulnerabilities.
Implement network segmentation to limit the impact of potential attacks.

Patching and Updates

Apply security patches provided by Quagga to address the CVE-2018-5381 vulnerability.