==================================================================== CERT-Renater Note d'Information No. 2021/VULN103 _____________________________________________________________________ DATE : 18/02/2021 HARDWARE PLATFORM(S): / OPERATING SYSTEM(S): Windows running Cisco AnyConnect Secure Mobility Client versions prior to 4.9.05042. ===================================================================== https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-anyconnect-dll-hijac-JrcTOQMC _____________________________________________________________________ Cisco AnyConnect Secure Mobility Client for Windows with VPN Posture (HostScan) Module DLL Hijacking Vulnerability High Advisory ID: cisco-sa-anyconnect-dll-hijac-JrcTOQMC First Published: 2021 February 17 16:00 GMT Version 1.0: Final Workarounds: No workarounds available Cisco Bug IDs: CSCvv64243 CVSS Score: Base 7.8 CVE-2021-1366 CWE-347 Summary A vulnerability in the interprocess communication (IPC) channel of Cisco AnyConnect Secure Mobility Client for Windows could allow an authenticated, local attacker to perform a DLL hijacking attack on an affected device if the VPN Posture (HostScan) Module is installed on the AnyConnect client. This vulnerability is due to insufficient validation of resources that are loaded by the application at run time. An attacker could exploit this vulnerability by sending a crafted IPC message to the AnyConnect process. A successful exploit could allow the attacker to execute arbitrary code on the affected machine with SYSTEM privileges. To exploit this vulnerability, the attacker needs valid credentials on the Windows system. 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-anyconnect-dll-hijac-JrcTOQMC Affected Products Vulnerable Products This vulnerability affects Cisco AnyConnect Secure Mobility Client for Windows releases earlier than Release 4.9.05042 that have the VPN Posture (HostScan) Module installed. Note: The VPN Posture (HostScan) Module should not be confused with the ISE Posture Module. The ISE Posture Module is not affected by this vulnerability. Products Confirmed Not Vulnerable 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 Cisco products: AnyConnect Secure Mobility Client for Linux AnyConnect Secure Mobility Client for Mac OS AnyConnect Secure Mobility Client for mobile device operating systems such as iOS, Android, and Universal Windows Platform AnyConnect Secure Mobility Client for Windows with only the ISE Posture Module installed Workarounds There are no workarounds that address this vulnerability. Fixed Software 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 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 Cisco AnyConnect Secure Mobility Client for Windows releases 4.9.05042 and later. To download the software from the Software Center on Cisco.com, do the following: Click Browse all. Choose Security > VPN and Endpoint Security Clients > Cisco VPN Clients > AnyConnect Secure Mobility Client > AnyConnect Secure Mobility Client v4.x. Choose a release from the left pane of the AnyConnect Secure Mobility Client v4.x page. Exploitation and Public Announcements 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 Cisco would like to thank Marcos Accossatto and Pablo Zurro of Core Security for reporting this vulnerability. URL https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-anyconnect-dll-hijac-JrcTOQMC Revision History Version Description Section Status Date 1.0 Initial public release. — Final 2021-FEB-17 Legal Disclaimer THIS DOCUMENT IS PROVIDED ON AN "AS IS" BASIS AND DOES NOT IMPLY ANY KIND OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. YOUR USE OF THE INFORMATION ON THE DOCUMENT OR MATERIALS LINKED FROM THE DOCUMENT IS AT YOUR OWN RISK. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE THIS DOCUMENT AT ANY TIME. A standalone copy or paraphrase of the text of this document that omits the distribution URL is an uncontrolled copy and may lack important information or contain factual errors. The information in this document is intended for end users of Cisco products. ========================================================= + CERT-RENATER | tel : 01-53-94-20-44 + + 23/25 Rue Daviel | fax : 01-53-94-20-41 + + 75013 Paris | email:cert@support.renater.fr + =========================================================