Cisco Security Advisory
Cisco ASR 5000 Series Aggregation Services Routers Enhanced Charging Service Rule Bypass Vulnerability
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CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N/E:X/RL:X/RC:X
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A vulnerability in the Enhanced Charging Service (ECS) functionality of Cisco ASR 5000 Series Aggregation Services Routers could allow an unauthenticated, remote attacker to bypass the traffic classification rules on an affected device.
The vulnerability is due to insufficient input validation of user traffic going through an affected device. An attacker could exploit this vulnerability by sending a malformed HTTP request to an affected device. A successful exploit could allow the attacker to bypass the traffic classification rules and potentially avoid being charged for traffic consumption.
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://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asr5k-ecs-bypass-2LqfPCL
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Vulnerable Products
At the time of publication, this vulnerability affected Cisco ASR 5000 Series Aggregation Services Routers if they were running a software release earlier than Release 21.18.0 and had an ECS rule configured to match on the CONNECT HTTP method.
Note: To determine whether an ECS rule is configured to match on the CONNECT HTTP method, administrators can use the show active-charging ruledef all command and search for http request method = connect in the results.
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.
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There are no workarounds that address this vulnerability.
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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 ASR 5000 Aggregation Services Routers software releases 21.18.0 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.
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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.
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This vulnerability was found during the resolution of a Cisco TAC support case.
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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.
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Show LessVersion Description Section Status Date 1.0 Initial public release. - Final 2020-JUN-17
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