CVE-2018-0155
Published on March 28, 2018
A vulnerability in the Bidirectional Forwarding Detection (BFD) offload implementation of Cisco Catalyst 4500 Series Switches and Cisco Catalyst 4500-X Series Switches could allow an unauthenticated, remote attacker to cause a crash of the iosd process, causing a denial of service (DoS) condition. The vulnerability is due to insufficient error handling when the BFD header in a BFD packet is incomplete. An attacker could exploit this vulnerability by sending a crafted BFD message to or across an affected switch. A successful exploit could allow the attacker to trigger a reload of the system. This vulnerability affects Catalyst 4500 Supervisor Engine 6-E (K5), Catalyst 4500 Supervisor Engine 6L-E (K10), Catalyst 4500 Supervisor Engine 7-E (K10), Catalyst 4500 Supervisor Engine 7L-E (K10), Catalyst 4500E Supervisor Engine 8-E (K10), Catalyst 4500E Supervisor Engine 8L-E (K10), Catalyst 4500E Supervisor Engine 9-E (K10), Catalyst 4500-X Series Switches (K10), Catalyst 4900M Switch (K5), Catalyst 4948E Ethernet Switch (K5). Cisco Bug IDs: CSCvc40729.
Known Exploited Vulnerability
This Cisco Catalyst Bidirectional Forwarding Detection Denial-of-Service Vulnerability is part of CISA's list of Known Exploited Vulnerabilities. A vulnerability in the Bidirectional Forwarding Detection (BFD) offload implementation of Cisco Catalyst 4500 Series Switches and Cisco Catalyst 4500-X Series Switches could allow an unauthenticated, remote attacker to cause a crash of the iosd process, causing a denial-of-service (DoS) condition.
The following remediation steps are recommended / required by March 17, 2022: Apply updates per vendor instructions.
Vulnerability Analysis
CVE-2018-0155 can be exploited with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. This vulnerability is known to be actively exploited by threat actors in an automatable fashion. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a high impact on availability.
Weakness Type
7PK - Errors
This category represents one of the phyla in the Seven Pernicious Kingdoms vulnerability classification. It includes weaknesses that occur when an application does not properly handle errors that occur during processing. According to the authors of the Seven Pernicious Kingdoms, "Errors and error handling represent a class of API. Errors related to error handling are so common that they deserve a special kingdom of their own. As with 'API Abuse,' there are two ways to introduce an error-related security vulnerability: the most common one is handling errors poorly (or not at all). The second is producing errors that either give out too much information (to possible attackers) or are difficult to handle."
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.