Cisco Secure Web Appliance Content Encoding Filter Bypass (cisco-sa-wsa-bypass-vXvqwzsj)

medium Nessus Plugin ID 181789

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Synopsis

The remote device is missing a vendor-supplied security patch.

Description

According to its self-reported version, the scanning engines of Cisco AsyncOS Software for Cisco Secure Web Appliance could allow an unauthenticated, remote attacker to bypass a configured rule, allowing traffic onto a network that should have been blocked. This vulnerability is due to improper detection of malicious traffic when the traffic is encoded with a specific content format. An attacker could exploit this vulnerability by using an affected device to connect to a malicious server and receiving crafted HTTP responses. A successful exploit could allow the attacker to bypass an explicit block rule and receive traffic that should have been rejected by the device.

This vulnerability affects Cisco Secure Web Appliance, both virtual and hardware versions, when the deflate, lzma, or brotli content-encoding type is enabled. The deflate content-encoding type is disabled by default, but the lzma and brotli content-encoding types are enabled by default.

Please see the included Cisco BIDs and Cisco Security Advisory for more information.

Solution

Disable deflate, lzma, and brotli content-encoding types or upgrade to the relevant fixed version referenced in Cisco bug IDs CSCwf55917, CSCwf60901, CSCwf94501

Plugin Details

Severity: Medium

ID: 181789

File Name: cisco-sa-wsa-bypass-vXvqwzsj.nasl

Version: 1.0

Type: combined

Family: CISCO

Published: 9/22/2023

Updated: 9/22/2023

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Low

Score: 1.4

CVSS v2

Risk Factor: Medium

Base Score: 5

Temporal Score: 3.7

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:P/A:N

CVSS Score Source: CVE-2023-20215

CVSS v3

Risk Factor: Medium

Base Score: 5.3

Temporal Score: 4.6

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

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

CPE: cpe:/h:cisco:web_security_appliance, cpe:/a:cisco:web_security_appliance, cpe:/o:cisco:web_security_appliance, cpe:/o:cisco:asyncos

Required KB Items: Host/AsyncOS/Cisco Web Security Appliance/DisplayVersion, Host/AsyncOS/Cisco Web Security Appliance/Version

Exploit Ease: No known exploits are available

Patch Publication Date: 8/2/2023

Vulnerability Publication Date: 8/2/2023

Reference Information

CVE: CVE-2023-20215

CISCO-SA: cisco-sa-wsa-bypass-vXvqwzsj

IAVA: 2023-A-0495

CISCO-BUG-ID: CSCwf55917, CSCwf60901, CSCwf94501

Detections

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