Horizon Alert
Summary of the vulnerability and why it matters
A vulnerability exists in Cisco IOS software related to Network Address Translation (NAT). This flaw could enable an unauthenticated attacker to disrupt services on affected devices. The issue stems from how the system handles specific network messages, potentially leading to device instability.
- Cisco IOS NAT functionality
- Improper handling of H.323 RAS messages
- Denial of service on devices
Attack Path
How an attacker could exploit the issue
A vulnerability exists in Cisco IOS devices that handle Network Address Translation (NAT) for H.323 protocol messages. This vulnerability could allow an unauthenticated, remote attacker to cause a denial of service by sending specially crafted H.323 Registration, Admission, and Status (RAS) packets. Successful exploitation could lead to a device crash and reload, impacting network availability. This affects devices configured with NAT application layer gateways for H.323 RAS messages, which are typically enabled by default.
- Network-accessible devices with NAT ALG enabled.
- Attacker sends crafted H.323 RAS packet.
- Device crashes, causing a denial of service.
Live Threat
Current exploitation, exposure, and threat context
This vulnerability could allow an unauthenticated attacker to cause a denial of service on affected Cisco devices. Exploitation requires the device to be configured with specific Network Address Translation (NAT) functionality for H.323 messages. Successful exploitation could lead to device reloads and service disruption.
- Attackers require moderate skill.
- Network access and specific configurations needed.
- Business risk involves service disruption.
Priority actions
Operational Fix
Recommended remediation, mitigation, and detection steps
This vulnerability in Cisco IOS NAT functionality could enable an unauthenticated, remote attacker to cause a denial of service by sending a crafted H.323 RAS packet. The attack exploits improper translation of H.323 messages, potentially leading to a device crash and reload. Organizations with affected Cisco devices configured for NAT with H.323 RAS messages should take immediate action to mitigate this risk.
- Find affected assets.
- Reduce exposure or isolate risk.
- Fix, verify, and monitor.
