Symptom
A vulnerability in the Session Initiation Protocol (SIP) inspection engine of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause an affected device to reload or trigger high CPU, resulting in a denial of service (DoS) condition.
The vulnerability is due to improper handling of SIP traffic. An attacker could exploit this vulnerability by sending SIP requests designed to specifically trigger this issue at a high rate across an affected device.
Software updates that address this vulnerability are not yet available. There are no workarounds that address this vulnerability. Mitigation options that address this vulnerability are available.
This advisory is available at the following link:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20181031-asaftd-sip-dos
Conditions
Please refer to the Security Advisory
Workaround
Please refer to the Security Advisory
Further Problem Description
Please refer to the Security Advisory
PSIRT Evaluation
The Cisco PSIRT has assigned this bug the following CVSS version 3 score. The Base CVSS score as of the time of evaluation is 8.6:
https://tools.cisco.com/security/center/cvssCalculator.x?version=3.0&vector=CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
CVE ID CVE-2018-15454 has been assigned to document this issue.
Additional information on Cisco's security vulnerability policy can be found at the following URL:
http://www.cisco.com/en/US/products/products_security_vulnerability_policy.html
