Horizon Alert
Summary of the vulnerability and why it matters
A vulnerability exists in the DHCP option 82 encapsulation feature within Cisco IOS Software and Cisco IOS XE Software. This flaw allows an unauthenticated, remote attacker to trigger a device reload, leading to a denial of service. The issue stems from incomplete input validation of specific DHCP information received from relay agents.
- Cisco IOS and IOS XE Software
- Incomplete DHCP option 82 input validation
- Denial of service condition
Attack Path
How an attacker could exploit the issue
This vulnerability affects network devices that process DHCP Version 4 packets. An attacker can send a specially crafted DHCP packet to an affected device. Successful exploitation could cause the device to stop functioning.
- External network exposure
- Attacker sends crafted packet
- Device reloads, causing denial of service
Live Threat
Current exploitation, exposure, and threat context
The identified vulnerability impacts network devices by allowing a remote attacker to cause a denial of service condition, leading to device reloads. This occurs due to incomplete input validation of DHCP option 82 information. Attackers could exploit this by sending crafted DHCP packets, potentially disrupting network services.
- Attacker skill level: Low
- Required access or conditions: Network access to DHCP relay
- Business risk or urgency: Potential denial of service
Priority actions
Operational Fix
Recommended remediation, mitigation, and detection steps
This vulnerability impacts Cisco IOS and IOS XE Software, potentially allowing an unauthenticated remote attacker to cause a denial-of-service condition by reloading an affected device. The issue stems from incomplete input validation of DHCP option 82 information received in DHCPv4 packets. Exploitation could disrupt device operations and impact network availability.
- Find affected devices using DHCP relay functionality.
- Restrict or isolate DHCP relay interfaces.
- Apply vendor fixes and validate.
- Monitor for related network disruptions.
