title: Cisco Umbrella Secure Web Gateway File Decryption Bypass Vulnerability
description: A vulnerability in the automatic decryption process in Cisco Umbrella Secure Web Gateway (SWG) could allow an authenticated, adjacent attacker to bypass the SSL decryption and content filtering policies on an affected system. This vulnerability is due to how the decryption function uses the TLS Sever Name Indication (SNI) extension of an HTTP request to discover the destination domain and determine if the request needs to be decrypted. An attacker could exploit this vulnerability by sending a crafted request over TLS from a client to an unknown or controlled URL. A successful exploit could allow an attacker to bypass the decryption process of Cisco Umbrella SWG and allow malicious content to be downloaded to a host on a protected network. There are workarounds that address this vulnerability.
problem types: CWE-693
affected:
{
product: Cisco Umbrella Insights Virtual Appliance
vendor: Cisco
versions:
status: affected, version: n/a
}
metrics:
cvssV3_1: [
attackComplexity: LOW
attackVector: ADJACENT_NETWORK
availabilityImpact: NONE
baseScore: 4.1
baseSeverity: MEDIUM
confidentialityImpact: NONE
integrityImpact: LOW
privilegesRequired: LOW
scope: CHANGED
userInteraction: NONE
vectorString: CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:N/I:L/A:N
version: 3.1
]
exploits: The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.