CVE-2017-3224 Information

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).

CVSS Vector

CVSS:3.0/AV:A/AC:H/PR:N/UI:N/S:C/C:L/I:H/A:H

Reference

https://www.kb.cert.org/vuls/id/793496

Attack Complexity

HIGH

Privileges Required

NONE

User Interaction Required

NONE

Scope

NONE

Confidentiality Impact

CHANGED

Integrity Impact

LOW

Availability Impact

HIGH

Base Score

HIGH

Base Severity

8.2