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AUSCERT External Security Bulletin Redistribution
ESB-2020.2120
Cisco Email Security Appliance URL Filtering Bypass Vulnerability
18 June 2020
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AusCERT Security Bulletin Summary
---------------------------------
Product: Cisco Email Security Appliance
Publisher: Cisco Systems
Operating System: Cisco
Impact/Access: Unauthorised Access -- Remote/Unauthenticated
Resolution: Patch/Upgrade
CVE Names: CVE-2020-3368
Original Bulletin:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-esa-url-bypass-WO4BZ75s
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Cisco Email Security Appliance URL Filtering Bypass Vulnerability
Priority: Medium
Advisory ID: cisco-sa-esa-url-bypass-WO4BZ75s
First Published: 2020 June 17 16:00 GMT
Version 1.0: Final
Workarounds: No workarounds availableCisco Bug IDs: CSCvs66918
CVE-2020-3368
CWE-20
CVSS Score:
5.8 AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N/E:X/RL:X/RC:X
Summary
o A vulnerability in the antispam protection mechanisms of Cisco AsyncOS
Software for Cisco Email Security Appliance (ESA) could allow an
unauthenticated, remote attacker to bypass the URL reputation filters on an
affected device.
The vulnerability is due to insufficient input validation of URLs. An
attacker could exploit this vulnerability by crafting the URL in a
particular way. A successful exploit could allow the attacker to bypass the
URL reputation filters that are configured for the affected device, which
could allow malicious URLs to pass through the device.
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-esa-url-bypass-WO4BZ75s
Affected Products
o Vulnerable Products
At the time of publication, this vulnerability affected Cisco AsyncOS
Software for Cisco ESA releases earlier than Release 13.5.0.
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 and Alerts 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, Cisco AsyncOS Software for Cisco ESA releases
13.5.0 and later contained the fix for this vulnerability.
See the Details section in the bug ID(s) at the top of this advisory for
the most complete and current information.
Exploitation and Public Announcements
o The Cisco Product Security Incident Response Team (PSIRT) is not aware of
any public announcements or malicious use of the vulnerability that is
described in this advisory.
Source
o This vulnerability was found during internal security testing.
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-esa-url-bypass-WO4BZ75s
Revision History
o +----------+---------------------------+----------+--------+--------------+
| Version | Description | Section | Status | Date |
+----------+---------------------------+----------+--------+--------------+
| 1.0 | Initial public release. | - | Final | 2020-JUN-17 |
+----------+---------------------------+----------+--------+--------------+
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