Horizon Alert
Summary of the vulnerability and why it matters
Certain Cisco devices running IOS and IOS XE Software are vulnerable due to improper handling of DHCP Version 4 (DHCPv4) packets. This flaw could allow an attacker to send a specially crafted packet, causing an affected device to reload. Such an event could disrupt network services, leading to a denial of service for organizations relying on these devices.
- Affected Cisco software versions
- Flaw in validating DHCP option data
- Disruption of network services
Attack Path
How an attacker could exploit the issue
Attackers can exploit a vulnerability in Cisco's DHCP functionality to cause a denial-of-service condition on affected devices. This occurs when the software improperly validates encapsulated option 82 information within DHCP Version 4 packets. By sending a specially crafted DHCPv4 packet, an attacker can trigger an error in the device's response processing, leading to a system reload. This reload disrupts network services, impacting device availability.
- Affected devices process DHCPv4 packets.
- Attacker sends crafted DHCPv4 packet.
- Device reloads, causing service denial.
Live Threat
Current exploitation, exposure, and threat context
This vulnerability could allow an unauthenticated attacker to disrupt network services by causing devices to reload, leading to a denial-of-service condition. The exploit requires the attacker to send a specially crafted DHCPv4 packet to an affected device. The potential for network disruption and service unavailability poses a significant business risk.
- Likely attacker skill level: Low
- Required access or conditions: Network access
- Business risk or urgency: High
Priority actions
Operational Fix
Recommended remediation, mitigation, and detection steps
A vulnerability in Cisco IOS and IOS XE Software could allow an unauthenticated, remote attacker to cause a denial-of-service condition. The vulnerability exists due to incomplete input validation of encapsulated option 82 information received in DHCPv4 packets. An attacker could exploit this by sending a crafted DHCPv4 packet, potentially causing an affected device to reload. This could impact network availability and business operations.
- Find exposed Cisco devices.
- Isolate affected network segments.
- Apply vendor updates; verify fixes.
- Monitor network traffic for anomalies.
