CVE-2017-3224: Open Shortest Path First (OSPF) protocol implementations may improperly determine Link State Advertisement (LSA) recency for LSAs with MaxSequenceNumb...

Description

Open Shortest Path First (OSPF) protocol implementations may improperly determine Link State Advertisement (LSA) recency for LSAs with MaxSequenceNumber. According to RFC 2328 section 13.1, for two instances of the same LSA, recency is determined by first comparing sequence numbers, then checksums, and finally MaxAge. In a case where the sequence numbers are the same, the LSA with the larger checksum is considered more recent, and will not be flushed from the Link State Database (LSDB). Since the RFC does not explicitly state that the values of links carried by a LSA must be the same when prematurely aging a self-originating LSA with MaxSequenceNumber, it is possible in vulnerable OSPF implementations for an attacker to craft a LSA with MaxSequenceNumber and invalid links that will result in a larger checksum and thus a 'newer' LSA that will not be flushed from the LSDB. Propagation of the crafted LSA can result in the erasure or alteration of the routing tables of routers within the routing domain, creating a denial of service condition or the re-routing of traffic on the network. CVE-2017-3224 has been reserved for Quagga and downstream implementations (SUSE, openSUSE, and Red Hat packages).

Metrics

EPSS Probability

1.06%

60.4th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Quagga	Quagga	All versions
Suse	Opensuse	All versions
Suse	Suse Linux	All versions
Redhat	Package Manager	All versions

References

https://www.kb.cert.org/vuls/id/793496Third Party Advisory, US Government Resource
https://www.kb.cert.org/vuls/id/793496Third Party Advisory, US Government Resource

Timeline

Published: Jul 24, 2018
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2017-3224?

Open Shortest Path First (OSPF) protocol implementations may improperly determine Link State Advertisement (LSA) recency for LSAs with MaxSequenceNumber. According to RFC 2328 section 13.1, for two instances of the same LSA, recency is determined by first comparing sequence numbers, then checksums, and finally MaxAge. In a case where the sequence numbers are the same, the LSA with the larger checksum is considered more recent, and will not be flushed from the Link State Database (LSDB). Since the RFC does not explicitly state that the values of links carried by a LSA must be the same when prematurely aging a self-originating LSA with MaxSequenceNumber, it is possible in vulnerable OSPF implementations for an attacker to craft a LSA with MaxSequenceNumber and invalid links that will result in a larger checksum and thus a 'newer' LSA that will not be flushed from the LSDB. Propagation of the crafted LSA can result in the erasure or alteration of the routing tables of routers within the routing domain, creating a denial of service condition or the re-routing of traffic on the network. CVE-2017-3224 has been reserved for Quagga and downstream implementations (SUSE, openSUSE, and Red Hat packages).

How severe is CVE-2017-3224?

Severity scoring for CVE-2017-3224 is pending analysis. The EPSS model estimates a 1.06% probability of exploitation in the next 30 days.

How do I fix CVE-2017-3224?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.