title: Cisco IOS XE Software for Cisco Catalyst 9300 Series Switches Secure Boot Bypass Vulnerability
description: A vulnerability in Cisco IOS XE Software for Cisco Catalyst 9300 Series Switches could allow an authenticated, local attacker with level-15 privileges or an unauthenticated attacker with physical access to the device to execute persistent code at boot time and break the chain of trust. This vulnerability is due to errors that occur when retrieving the public release key that is used for image signature verification. An attacker could exploit this vulnerability by modifying specific variables in the Serial Peripheral Interface (SPI) flash memory of an affected device. A successful exploit could allow the attacker to execute persistent code on the underlying operating system. Note: In Cisco IOS XE Software releases 16.11.1 and later, the complexity of an attack using this vulnerability is high. However, an attacker with level-15 privileges could easily downgrade the Cisco IOS XE Software on a device to a release that would lower the attack complexity.
problem types: CWE-78
affected:
{
vendor: Cisco
product: Cisco IOS XE ROMMON Software
versions:
version: n/a, status: affected
}
metrics:
cvssV3_1: [
version: 3.1
vectorString: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
attackVector: PHYSICAL
attackComplexity: LOW
privilegesRequired: NONE
userInteraction: NONE
scope: UNCHANGED
confidentialityImpact: HIGH
integrityImpact: HIGH
availabilityImpact: NONE
baseScore: 6.1
baseSeverity: MEDIUM
]
exploits: The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.