CVE-2023-20006
HighCVSS 8.6Exploitation Probability (EPSS)
Elevated risk57th percentile - higher than 57% of all known CVEs
Summary
A vulnerability in the hardware-based SSL/TLS cryptography functionality of Cisco Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD) Software for Firepower 2100 Series Appliances could allow an unauthenticated, remote attacker to cause an unexpected reload, resulting in a denial of service (DoS). This is due to an implementation error in cryptographic functions when offloaded to hardware. An attacker could exploit this by sending a crafted stream of SSL/TLS traffic.
Risk Assessment
The risk is that a remote attacker can disrupt security appliance operations, potentially causing network unavailability.
Recommendation
It is recommended to update ASA/FTD software to a patched version and limit exposure to untrusted SSL/TLS traffic.
Other vulnerabilities in Cisco Adaptive Security Appliance
See all- CVE-2024-20485Medium
A vulnerability in the VPN web server of Cisco ASA and FTD Software allows an authenticated local attacker with administrator privileges to execute arbitrary code with root privileges. This is due to improper validation of a specific file when read from system flash memory.
- CVE-2023-20107High
A vulnerability in the deterministic random bit generator (DRBG) in Cisco Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD) Software for ASA 5506-X, ASA 5508-X, and ASA 5516-X Firewalls could allow an unauthenticated, remote attacker to cause a cryptographic collision, enabling discovery of the device's private key. This is due to insufficient entropy in the DRBG on these hardware platforms. An attacker could exploit this by generating many keys and looking for collisions with target devices.
- CVE-2022-20947High
A vulnerability in dynamic access policies (DAP) functionality of Cisco Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a device reload, resulting in a denial of service (DoS). This is due to improper processing of HostScan data from the Posture module. An attacker could exploit this by sending crafted HostScan data.
- CVE-2022-20924High
A vulnerability in the Simple Network Management Protocol (SNMP) feature of Cisco Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD) Software could allow an authenticated, remote attacker to cause a denial of service (DoS). This is due to insufficient input validation. An attacker could exploit this by sending a crafted SNMP request, causing a device reload.
- CVE-2022-20715High
A vulnerability in the remote access SSL VPN features of Cisco ASA and FTD Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition. This is due to improper validation of logged errors from client connections. An attacker could exploit this by sending crafted requests, causing the device to restart.
- CVE-2021-1422High
A vulnerability in the software cryptography module of Cisco ASA and FTD Software could allow an authenticated, remote attacker or an unauthenticated attacker in a man-in-the-middle position to cause an unexpected reload of the device, resulting in a denial of service (DoS) condition. This is due to a logic error in handling specific decryption errors. An attacker could exploit this by sending malicious packets over an established IPsec connection, causing a crash and reload. Important: Successful exploitation would not compromise encrypted data. This affects only ASA 9.16.1 and FTD 7.0.0.
- CVE-2021-1493High
A vulnerability in the web services interface of Cisco ASA and FTD Software could allow an authenticated, remote attacker to cause a buffer overflow on an affected system. This is due to insufficient boundary checks for specific data. An attacker could exploit this by sending a malicious HTTP request, potentially disclosing data fragments or causing a device reload and DoS.
- CVE-2020-3436High
A vulnerability in the web services interface of Cisco ASA and FTD Software could allow an unauthenticated, remote attacker to upload arbitrary-sized files to specific folders, leading to an unexpected device reload. The issue is due to inefficient handling of large file writes. An attacker could upload files to trigger a watchdog timeout, causing device reload and DoS.
- CVE-2020-3306High
A vulnerability in the DHCP module of Cisco ASA and FTD Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on the affected device. This is due to incorrect processing of certain DHCP packets. An attacker could exploit this by sending a crafted DHCP packet, causing a DoS.
- CVE-2020-3305High
A vulnerability in the implementation of the Border Gateway Protocol (BGP) module in Cisco ASA and FTD Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition. This is due to incorrect processing of certain BGP packets. An attacker could exploit this by sending a crafted BGP packet, causing a DoS.
Original NVD description (English source)
A vulnerability in the hardware-based SSL/TLS cryptography functionality of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software for Cisco Firepower 2100 Series Appliances could allow an unauthenticated, remote attacker to cause an affected device to reload unexpectedly, resulting in a denial of service (DoS) condition. This vulnerability is due to an implementation error within the cryptographic functions for SSL/TLS traffic processing when they are offloaded to the hardware. An attacker could exploit this vulnerability by sending a crafted stream of SSL/TLS traffic to an affected device. A successful exploit could allow the attacker to cause an unexpected error in the hardware-based cryptography engine, which could cause the device to reload.

