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AUSCERT External Security Bulletin Redistribution
ESB-2022.1493
Cisco Web Security Appliance Filter Bypass Vulnerability
7 April 2022
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AusCERT Security Bulletin Summary
---------------------------------
Product: Web Security Appliance (WSA)
Publisher: Cisco Systems
Operating System: Cisco
Resolution: Patch/Upgrade
CVE Names: CVE-2022-20784
Original Bulletin:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-swa-filter-bypass-XXXTU3X
Comment: CVSS (Max): 5.8 CVE-2022-20784 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N)
CVSS Source: Cisco Systems
Calculator: https://www.first.org/cvss/calculator/3.1#CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
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Cisco Web Security Appliance Filter Bypass Vulnerability
Priority: Medium
Advisory ID: cisco-sa-swa-filter-bypass-XXXTU3X
First Published: 2022 April 6 16:00 GMT
Version 1.0: Final
Workarounds: No workarounds available
Cisco Bug IDs: CSCvx78607
CVE Names: CVE-2022-20784
CWEs: CWE-20
Summary
o A vulnerability in the Web-Based Reputation Score (WBRS) engine of Cisco
AsyncOS Software for Cisco Web Security Appliance (WSA) could allow an
unauthenticated, remote attacker to bypass established web request policies
and access blocked content on an affected device.
This vulnerability is due to incorrect handling of certain character
combinations inserted into a URL. An attacker could exploit this
vulnerability by sending crafted URLs to be processed by an affected
device. A successful exploit could allow the attacker to bypass the web
proxy and access web content that has been blocked by policy.
Cisco has released software updates that address this vulnerability. There
are no workarounds that address this vulnerability.
This advisory is available at the following link:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-swa-filter-bypass-XXXTU3X
Affected Products
o Vulnerable Products
At the time of publication, this vulnerability affected Cisco WSA, both
virtual and hardware appliances.
For information about which Cisco software releases were vulnerable at the
time of publication, see the Fixed Software section of this advisory. See
the Details section in the bug ID(s) at the top of this advisory for the
most complete and current information.
Products Confirmed Not Vulnerable
Only products listed in the Vulnerable Products section of this advisory
are known to be affected by this vulnerability.
Workarounds
o There are no workarounds that address this vulnerability.
Fixed Software
o When considering software upgrades , customers are advised to regularly
consult the advisories for Cisco products, which are available from the
Cisco Security Advisories page , to determine exposure and a complete
upgrade solution.
In all cases, customers should ensure that the devices to be upgraded
contain sufficient memory and confirm that current hardware and software
configurations will continue to be supported properly by the new release.
If the information is not clear, customers are advised to contact the Cisco
Technical Assistance Center (TAC) or their contracted maintenance
providers.
Fixed Releases
At the time of publication, the release information in the following table
(s) was accurate. See the Details section in the bug ID(s) at the top of
this advisory for the most complete and current information.
The left column lists Cisco software releases, and the right column
indicates whether a release was affected by the vulnerability described in
this advisory and which release included the fix for this vulnerability.
Cisco WSA Release First Fixed Release
Earlier than 11.7. Not vulnerable.
11.7 Migrate to a fixed release.
11.8 Migrate to a fixed release.
12.0 Migrate to a fixed release.
12.5 Migrate to a fixed release.
14.0 14.0.2
14.5 Not vulnerable.
The Cisco Product Security Incident Response Team (PSIRT) validates only
the affected and fixed release information that is documented in this
advisory.
Exploitation and Public Announcements
o The Cisco PSIRT is not aware of any public announcements or malicious use
of the vulnerability that is described in this advisory.
Source
o Cisco would like to thank Seyed Amirhossein Nouraie of XOR Security for
reporting this vulnerability.
Cisco Security Vulnerability Policy
o To learn about Cisco security vulnerability disclosure policies and
publications, see the Security Vulnerability Policy . This document also
contains instructions for obtaining fixed software and receiving security
vulnerability information from Cisco.
URL
o https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-swa-filter-bypass-XXXTU3X
Revision History
o +----------+---------------------------+----------+--------+--------------+
| Version | Description | Section | Status | Date |
+----------+---------------------------+----------+--------+--------------+
| 1.0 | Initial public release. | - | Final | 2022-APR-06 |
+----------+---------------------------+----------+--------+--------------+
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