Cisco Security Advisory
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CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:X/RL:X/RC:X
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A vulnerability in session management for the web-based interface of Cisco Small Business Smart and Managed Switches could allow an unauthenticated, remote attacker to defeat authentication protections and gain unauthorized access to the management interface. The attacker could obtain the privileges of the highjacked session account, which could include administrator privileges on the device.
The vulnerability is due to the use of weak entropy generation for session identifier values. An attacker could exploit this vulnerability to determine a current session identifier through brute force and reuse that session identifier to take over an ongoing session. In this way, an attacker could take actions within the management interface with privileges up to the level of the administrative user.
Cisco has released software updates that address this vulnerability for devices that have not reached the end of software maintenance. 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-sbswitch-session-JZAS5jnY
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Vulnerable Products
This vulnerability affects the following Cisco products if they are running a firmware release earlier than the first fixed release:
- 250 Series Smart Switches
- 350 Series Managed Switches
- 350X Series Stackable Managed Switches
- 550X Series Stackable Managed Switches
- Small Business 200 Series Smart Switches
- Small Business 300 Series Managed Switches
- Small Business 500 Series Stackable Managed Switches
For information about which Cisco firmware releases are vulnerable, see the Fixed Software section of this advisory.
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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Cisco has released free software updates for devices that have not reached the end of software maintenance to address the vulnerability described in this advisory. Customers may only install and expect support for software versions and feature sets for which they have purchased a license. By installing, downloading, accessing, or otherwise using such software upgrades, customers agree to follow the terms of the Cisco software license: https://www.cisco.com/c/en/us/products/end-user-license-agreement.html
Additionally, customers may only download software for which they have a valid license, procured from Cisco directly, or through a Cisco authorized reseller or partner. In most cases this will be a maintenance upgrade to software that was previously purchased. Free security software updates do not entitle customers to a new software license, additional software feature sets, or major revision upgrades.
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.
Customers Without Service Contracts
Customers who purchase directly from Cisco but do not hold a Cisco service contract and customers who make purchases through third-party vendors but are unsuccessful in obtaining fixed software through their point of sale should obtain upgrades by contacting the Cisco TAC: https://www.cisco.com/c/en/us/support/web/tsd-cisco-worldwide-contacts.html
Customers should have the product serial number available and be prepared to provide the URL of this advisory as evidence of entitlement to a free upgrade.
Fixed Releases
Cisco fixed this vulnerability in firmware release 2.5.5.47 for the following Cisco products:
- 250 Series Smart Switches
- 350 Series Managed Switches
- 350X Series Stackable Managed Switches
- 550X Series Stackable Managed Switches
Customers can download the firmware from the Software Center on Cisco.com by clicking Browse all and navigating to Switches > LAN Switches - Small Business.
The following Cisco products have passed the end-of-software-maintenance milestone. Although these switches are vulnerable, Cisco will not provide a firmware fix.
- Small Business 200 Series Smart Switches
- Small Business 300 Series Managed Switches
- Small Business 500 Series Stackable Managed Switches
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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-JUL-01
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