CVE-2018-0231
HighCVSS 8.6Exploitation Probability (EPSS)
Very high risk91th percentile - higher than 91% of all known CVEs
Summary
A vulnerability in the Transport Layer Security (TLS) library of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to trigger a reload of the affected device, resulting in a denial of service (DoS) condition. The vulnerability is due to insufficient validation of user-supplied input. An attacker could exploit this vulnerability by sending a malicious TLS message to an interface enabled for SSL services. Messages using SSLv3 or SSLv2 cannot be used to exploit this vulnerability. An exploit could cause a buffer underflow, triggering a crash. This affects ASAv, FTDv, and Firepower 2100 Series.
Risk Assessment
The risk includes the possibility of device disruption, leading to unavailability of network services. The attack does not require authentication, increasing the risk of remote attack.
Recommendation
It is recommended to apply Cisco ASA/FTD software updates that contain fixes for this vulnerability. Also, monitor devices for unusual TLS traffic.
Original NVD description (English source)
A vulnerability in the Transport Layer Security (TLS) library of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to trigger a reload of the affected device, resulting in a denial of service (DoS) condition. The vulnerability is due to insufficient validation of user-supplied input. An attacker could exploit this vulnerability by sending a malicious TLS message to an interface enabled for Secure Layer Socket (SSL) services on an affected device. Messages using SSL Version 3 (SSLv3) or SSL Version 2 (SSLv2) cannot be be used to exploit this vulnerability. An exploit could allow the attacker to cause a buffer underflow, triggering a crash on an affected device. This vulnerability affects Cisco ASA Software and Cisco FTD Software that is running on the following Cisco products: Adaptive Security Virtual Appliance (ASAv), Firepower Threat Defense Virtual (FTDv), Firepower 2100 Series Security Appliance. Cisco Bug IDs: CSCve18902, CSCve34335, CSCve38446.