Headline
CVE-2019-1816: Cisco Security Advisory: Cisco Web Security Appliance Privilege Escalation Vulnerability
A vulnerability in the log subscription subsystem of the Cisco Web Security Appliance (WSA) could allow an authenticated, local attacker to perform command injection and elevate privileges to root. The vulnerability is due to insufficient validation of user-supplied input on the web and command-line interface. An attacker could exploit this vulnerability by authenticating to the affected device and injecting scripting commands in the scope of the log subscription subsystem. A successful exploit could allow the attacker to execute arbitrary commands on the underlying operating system and elevate privileges to root.
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.htmlAdditionally, 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 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.
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.htmlCustomers 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
Customers are advised to upgrade to an appropriate release as indicated in the following table:
Cisco AsyncOS Software Major Release
First Fixed Release
10.1
10.1.4-017
10.5
10.5.4-018
11.5
11.5.2-020
11.7
11.7.0-406
In most cases, the software can be upgraded over the network by using the System Upgrade options in the web interface of the WSA. To upgrade a device by using the web interface:
- Choose System Administration > System Upgrade.
- Click Upgrade Options.
- Choose Download and Install.
- Choose the release to upgrade to.
- In the Upgrade Preparation area, choose the appropriate options.
- Click Proceed to begin the upgrade. A progress bar displays the status of the upgrade.
After the upgrade is complete, the device reboots.