CVE-2023-20006 - Unauthenticated DoS Vulnerability in Cisco ASA and FTD Software on Firepower 210 Series Appliances

A critical vulnerability (CVE-2023-20006) has been discovered 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 210 Series Appliances. This vulnerability enables an unauthenticated, remote attacker to cause a device to reload unexpectedly, leading to a denial of service (DoS) condition.

Description

This vulnerability is due to an implementation error in the cryptographic functions that process SSL/TLS traffic when it is offloaded to the hardware. An attacker can exploit this vulnerability by sending a specially crafted stream of SSL/TLS traffic to a vulnerable device. A successful exploit could allow the attacker to trigger an unexpected error in the hardware-based cryptography engine, which could cause the affected device to reload.

Here is a code snippet that demonstrates how an attacker could exploit this vulnerability

import socket
import ssl

# Replace with the target device's IP address
TARGET_IP = "192.168.1.1"

# Replace with the target device's SSL/TLS port number
TARGET_PORT = 443

# Craft the malicious SSL/TLS payload
malicious_payload = b" maliciousPayloadGoesHere " 

# Create a raw socket
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

# Wrap the raw socket with SSL/TLS
wrapped_socket = ssl.wrap_socket(sock)

# Connect to the target device
wrapped_socket.connect((TARGET_IP, TARGET_PORT))

# Send the malicious SSL/TLS payload
wrapped_socket.send(malicious_payload)

# Close the socket
wrapped_socket.close()

Original References

- Cisco Security Advisory: https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-dos-2FG5zQMS
- CVE-2023-20006 details: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-20006

Mitigation Steps

Cisco has released software updates that address this vulnerability. It is highly recommended that affected users update their devices to the latest versions. Users can refer to the Cisco Security Advisory for guidance on how to obtain and install the updated software.

Conclusion

The CVE-2023-20006 vulnerability poses a significant risk to organizations using Cisco ASA and FTD Software on Firepower 210 Series Appliances. Attackers can exploit this vulnerability to cause a denial of service (DoS) condition on affected devices, potentially leading to network disruptions. Users are urged to apply the necessary software updates as soon as possible to protect their network infrastructure.

Timeline

Published on: 06/28/2023 15:15:00 UTC
Last modified on: 07/12/2023 16:15:00 UTC