A vulnerability in the Secure Sockets Layer (SSL) VPN feature for Cisco Small Business RV VPN Routers could allow an unauthenticated, remote attacker to cause the device to unexpectedly restart, causing a denial of service (DoS) condition. The vulnerability is due to a lack of proper input validation of HTTP requests. An attacker could exploit this vulnerability by sending a crafted HTTP request over an SSL connection to the targeted device. A successful exploit could allow the attacker to cause a reload, resulting in a DoS condition. Cisco has released software updates that address the vulnerability described in this advisory. 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-sb-dos-ZN5GvNH7
A vulnerability in the Secure Sockets Layer (SSL) VPN feature for Cisco Small Business RV VPN Routers could allow an unauthenticated, remote attacker to cause the device to unexpectedly restart, causing a denial of service (DoS) condition.
The vulnerability is due to a lack of proper input validation of HTTP requests. An attacker could exploit this vulnerability by sending a crafted HTTP request over an SSL connection to the targeted device. A successful exploit could allow the attacker to cause a reload, resulting in a DoS condition.
Cisco has released software updates that address the vulnerability described in this advisory. 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-sb-dos-ZN5GvNH7
This vulnerability affects all releases of the following Cisco products if SSL VPN is configured on the device:
Only products listed in the Vulnerable Products section of this advisory are known to be affected by this vulnerability.
Cisco has confirmed that this vulnerability does not affect the following products:
Disabling the SSL VPN configuration eliminates the attack vector for this vulnerability, and may be a suitable mitigation until the affected device can be upgraded. The administrator can use the web-based utility to navigate to VPN > SSL VPN and set the radio button to Off.
Cisco has released free software updates that 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 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.
Cisco fixed this vulnerability in firmware release 1.0.03.18.
To download the software from the Software Center on Cisco.com, click Browse All and navigate to Downloads Home > Routers > Small Business Routers > Small Business RV Series Routers.
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.
Cisco would like to thank 0x00string with exploitee.rs for reporting this vulnerability.
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.
| Version | Description | Section | Status | Date |
|---|---|---|---|---|
| 1.0 | Initial public release. | - | Final | 2020-July-15 |
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