Horizon Alert
Summary of the vulnerability and why it matters
The DHCP relay subsystem in Cisco IOS and Cisco IOS XE Software has a vulnerability. This flaw could allow an unauthenticated, remote attacker to execute arbitrary code, taking full control of a system. In some cases, it could also cause the system to reload, leading to a denial-of-service condition. The core issue stems from a buffer overflow within the DHCP relay subsystem.
- Vulnerable DHCP relay subsystem
- Buffer overflow condition
- System control or denial of service
Attack Path
How an attacker could exploit the issue
This vulnerability allows an unauthenticated, remote attacker to execute arbitrary code and gain full control of an affected system. The attacker could also cause a system reload, leading to a denial of service. The vulnerability exists due to a buffer overflow in the DHCP relay subsystem. Exploitation involves sending a crafted DHCP Version 4 packet to an affected system.
- External network exposure required.
- Unauthenticated attacker sends crafted DHCP packet.
- Attacker gains code execution and control.
Live Threat
Current exploitation, exposure, and threat context
This vulnerability presents a significant risk to affected organizations due to its potential for remote exploitation and severe impact. An unauthenticated attacker could exploit a buffer overflow in the DHCP relay subsystem by sending a crafted DHCPv4 packet. Successful exploitation allows an attacker to execute arbitrary code, gain full control of the system, or cause a denial-of-service condition. Organizations should prioritize addressing this vulnerability.
- 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
This vulnerability could allow an unauthenticated, remote attacker to execute arbitrary code on affected systems, potentially leading to a complete system takeover or a denial-of-service condition. The risk stems from a buffer overflow in the DHCP relay subsystem, exploitable by sending a crafted DHCPv4 packet. Addressing this requires a structured approach to identify and mitigate the exposure across the organization's network infrastructure.
- Identify systems with the vulnerable DHCP relay function.
- Isolate or restrict access to the affected subsystem.
- Apply vendor patches and validate their effectiveness.
- Monitor for related network activity.
