Cisco Security Advisory
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CVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N/E:X/RL:X/RC:X
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On February 26th, 2020, researchers Štefan Svorencík and Robert Lipovsky disclosed a vulnerability in the implementation of the wireless egress packet processing of certain Broadcom Wi-Fi chipsets. This vulnerability could allow an unauthenticated, adjacent attacker to decrypt Wi-Fi frames without the knowledge of the Wireless Protected Access (WPA) or Wireless Protected Access 2 (WPA2) Pairwise Temporal Key (PTK) used to secure the Wi-Fi network.
The vulnerability exists because after an affected device handles a disassociation event it could send a limited number of Wi-Fi frames encrypted with a static, weak PTK. An attacker could exploit this vulnerability by acquiring these frames and decrypting them with the static PTK. A successful exploit could allow the attacker to decrypt Wi-Fi frames without the knowledge of the security session establishment used to secure the Wi-Fi network.
Multiple Cisco wireless products are affected by this vulnerability.
Cisco will release 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-20200226-wi-fi-info-disclosure
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Cisco is investigating its product line to determine which products may be affected by this vulnerability. As the investigation progresses, Cisco will update this advisory with information about affected products, including the ID of the Cisco bug for each affected product.
For information about whether a product is affected by this vulnerability, refer to the Vulnerable Products and Products Confirmed Not Vulnerable sections of this advisory. The Vulnerable Products section includes Cisco bug IDs for each affected product. The bugs are accessible through the Cisco Bug Search Tool and contain additional platform-specific information, including workarounds (if available) and fixed software releases.
Vulnerable Products
Product Cisco Bug ID Fixed Release Availability Routing and Switching - Enterprise and Service Provider Cisco Connected Grid Routers CSCvs87927 Routing and Switching - Small Business Cisco RV160x and RV260x VPN Routers CSCvt23810 Cisco RV340W Dual WAN Gigabit Wireless-AC VPN Router CSCvs87875 Cisco Small Business RV Series RV110W Wireless-N VPN Firewall CSCvs87870 Cisco Small Business RV Series RV215W Wireless-N VPN Router CSCvs87874 Cisco Small Business RV130 Series VPN Routers CSCvs87871 Cisco WAP125 Wireless-AC Dual Band Desktop Access Point with PoE CSCvs87868 Cisco WAP150 Wireless-AC/N Dual Radio Access Point with PoE CSCvs87877 Cisco WAP361 Wireless-AC/N Dual Radio Wall Plate Access Point with PoE CSCvs87877 Cisco WAP571 Wireless-AC/N Premium Dual Radio Access Point with PoE CSCvs93095 Cisco WAP571E Wireless-AC/N Premium Dual Radio Outdoor Access Point CSCvs93095 Voice and Unified Communications Devices Cisco IP Phone 8861 CSCvs87895 Cisco Wireless IP Phone 8821 CSCvs87896 Video, Streaming, TelePresence, and Transcoding Devices Cisco Webex Board (all models) CSCvs91690 Cisco Webex Desk Pro CSCvs91690 Cisco Webex Room Series CSCvs91690 Wireless Cisco Catalyst 9115 Series Wi-Fi 6 Access Points CSCvs87888 Cisco Catalyst 9120 Series Access Points CSCvs87888 Cisco Small Business 100 Series Wireless-N Access Points CSCvs87879 Cisco Small Business 300 Series Wireless-N Access Points CSCvs87879 Cisco Meraki MR26 N/A Cisco Meraki MR32 N/A Cisco Meraki MR34 N/A Cisco Meraki MR72 N/A Security Cisco Meraki MX64W N/A Cisco Meraki MX65W N/A For additional information about the impact of this vulnerability on Cisco Meraki, see the Cisco Meraki Customer Advisories.
Products Under Investigation
Voice and Unified Communications Devices
- DX650 IP Phones - Running Android-based firmware
Products Confirmed Not Vulnerable
Only products listed in the Vulnerable Products section of this advisory are known to be affected by this vulnerability.
Endpoint Clients and Client Software
- Cisco AnyConnect Secure Mobility Client - Network Access Manager
Routing and Switching - Enterprise and Service Provider
- Cisco 829 Industrial Integrated Services Routers
- Cisco c800 Series Integrated Services Routers
Routing and Switching - Small Business
- Cisco RV132W ADSL2+ Wireless-N VPN Router
- Cisco RV134W VDSL2 Wireless-AC VPN Router
Voice and Unified Communications Devices
- Cisco IP Phone 8800 Series with Multiplatform Firmware
- Cisco Unified IP Phone 8961
- Cisco Unified IP Phone 9951
- Cisco Unified IP Phone 9971
- Cisco Unified Wireless IP Phone 7925 and 7926
Video, Streaming, TelePresence, and Transcoding Devices
- Cisco TelePresence MX Series
- Cisco TelePresence Profile Series
- Cisco TelePresence SX Series
- Cisco TelePresence System EX Series
- Cisco Telepresence Integrator C Series
- Cisco Vision Dynamic Signage Director - SV-4K digital media player
Wireless
- Cisco Wireless LAN Controller
- Cisco Aironet 1560 Series Access Points
- Cisco Aironet 1810 Series OfficeExtend Access Points
- Cisco Aironet 1810w Series Access Points
- Cisco Aironet 1815 Series Access Points
- Cisco Aironet 1830 Series Access Points
- Cisco Aironet 1850 Series Access Points
- Cisco Aironet 2800 Series Access Points
- Cisco Aironet 3800 Series Access Points
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When a disassociation event is triggered, an affected device will delete the user-configured PTK as part of a sequence of cleanup operations. A number of Wi-Fi frames still buffered in the hardware egress queue could then be transmitted while encrypted with a static, weak PTK.
There are two ways to acquire Wi-Fi frames encrypted with the static PTK:
- Triggering the disassociation event by injecting malicious packets into the wireless network and capturing the frames sent after the event.
- Passively listening to traffic from the wireless network and capturing the frames sent after a disassociation event.
The frames affected by the weak encryption are the only ones present in the hardware egress buffer during the processing of a disassociation event. Further frames will not be accepted or queued. Under no circumstances can the attacker control the content or number of frames. This limits the information that can be obtained in case of successful exploitation of the vulnerability described in this advisory.
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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
See the Details section in the bug ID(s) in the Vulnerable Products section for the most complete and current information.
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The vulnerability described in this advisory was discussed during the RSA conference of February 26, 2020.
The Cisco Product Security Incident Response Team (PSIRT) is aware that proof-of-concept exploit code is available for the vulnerability that is described in this advisory.
Cisco PSIRT is not aware of any malicious use of the vulnerability that is described in this advisory.
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Security researchers Štefan Svorencík and Robert Lipovsky of ESET have reported this vulnerability to the Industry Consortium for Advancement of Security on the Internet (ICASI).
Cisco collaborated with ICASI during the investigation and disclosure of this vulnerability. More information can be found at http://www.icasi.org
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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 1.2 Updated Vulnerable Products, and included information about the impact of this vulnerability on Cisco Meraki products. Vulnerable Products Interim 2020-APR-28 1.1 Updated Vulnerable Products, Products Confirmed Not Vulnerable, and included information about publicly available code to exploit this vulnerability. Vulnerable Products, Products Confirmed Not Vulnerable Interim 2020-MAR-25 1.0 Initial public release. — Interim 2020-FEB-26
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