A vulnerability in the way software packages are loaded in Cisco IOS XE Software for the Cisco Aggregation Services Routers (ASR) 1000 Series could allow an authenticated, local attacker to gain restricted root shell access.
The vulnerability is due to lack of proper input validation of file names at the command-line interface (CLI). An attacker could exploit this vulnerability by authenticating to the affected device and crafting specific file names for use when loading packages. An exploit could allow the authenticated attacker to bypass the license required for root shell access. If the authenticated user obtains the root shell access, further compromise is possible.
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: http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20151130-asa