CVE-2018-0296: Cisco Adaptive Security Appliance (ASA) Denial-of-Service Vulnerability
A vulnerability in the web interface of the Cisco Adaptive Security Appliance (ASA) could allow an unauthenticated, remote attacker to cause an affected device to reload unexpectedly, resulting in a denial of service (DoS) condition. It is also possible on certain software releases that the ASA will not reload, but an attacker could view sensitive system information without authentication by using directory traversal techniques. The vulnerability is due to lack of proper input validation of the HTTP URL. An attacker could exploit this vulnerability by sending a crafted HTTP request to an affected device. An exploit could allow the attacker to cause a DoS condition or unauthenticated disclosure of information. This vulnerability applies to IPv4 and IPv6 HTTP traffic. This vulnerability affects Cisco ASA Software and Cisco Firepower Threat Defense (FTD) Software that is running on the following Cisco products: 3000 Series Industrial Security Appliance (ISA), ASA 1000V Cloud Firewall, ASA 5500 Series Adaptive Security Appliances, ASA 5500-X Series Next-Generation Firewalls, ASA Services Module for Cisco Catalyst 6500 Series Switches and Cisco 7600 Series Routers, Adaptive Security Virtual Appliance (ASAv), Firepower 2100 Series Security Appliance, Firepower 4100 Series Security Appliance, Firepower 9300 ASA Security Module, FTD Virtual (FTDv). Cisco Bug IDs: CSCvi16029.
Other sources
Cisco Adaptive Security Appliance (ASA) contains an improper input validation vulnerability with HTTP URLs. Exploitation could allow an attacker to cause a denial-of-service (DoS) condition or information disclosure.
— CISA
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Compensating control
Mitigate the ASA/FTD HTTP URL input-validation vulnerability by blocking or restricting inbound access to the affected HTTP web interface from untrusted networks (IPv4 and IPv6), since exploitation requires sending a crafted HTTP request.
- Compensating control
If the affected HTTP web interface is reachable, restrict access to it to trusted management sources only (e.g., trusted IPs/subnets) to prevent unauthenticated crafted-HTTP requests that could trigger reload/DoS or unauthorized information disclosure via directory traversal.
- Compensating control
Monitor for and prevent exploitation attempts that send crafted HTTP requests to the ASA/FTD web interface, including attempts consistent with HTTP URL directory traversal (unauthenticated sensitive system information disclosure).
Event History
Frequently Asked Questions
What is the severity of CVE-2018-0296?
The severity of CVE-2018-0296 is classified as a denial of service vulnerability.
How do I fix CVE-2018-0296?
To fix CVE-2018-0296, upgrade to the recommended software releases provided by Cisco.
What devices are affected by CVE-2018-0296?
CVE-2018-0296 affects various versions of Cisco Adaptive Security Appliance (ASA) and Firepower Threat Defense software.
Can CVE-2018-0296 be exploited remotely?
Yes, CVE-2018-0296 can be exploited by an unauthenticated remote attacker.
What impact does CVE-2018-0296 have on the system?
The impact of CVE-2018-0296 is an unexpected reload of the affected device, leading to a denial of service condition.