CVE-2017-3224
July 24, 2018
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).
Related ResourcesĀ (4)
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Contact UsCVSS v4
Base Score:
7.3
Attack Vector
ADJACENT
Attack Complexity
HIGH
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
NONE
Vulnerable System Confidentiality
LOW
Vulnerable System Integrity
HIGH
Vulnerable System Availability
HIGH
Subsequent System Confidentiality
LOW
Subsequent System Integrity
HIGH
Subsequent System Availability
HIGH
CVSS v3
Base Score:
8.2
Attack Vector
ADJACENT
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
CHANGED
Confidentiality
LOW
Integrity
HIGH
Availability
HIGH
CVSS v2
Base Score:
4.3
Access Vector
ADJACENT NETWORK
Access Complexity
MEDIUM
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
PARTIAL
Availability Impact
PARTIAL
Weakness Type (CWE)
EPSS
Base Score:
0.03