CVE-2017-3859: High severity Cisco IOS XE vulnerability
A vulnerability in the DHCP code for the Zero Touch Provisioning feature of Cisco ASR 920 Series Aggregation Services Routers could allow an unauthenticated, remote attacker to cause an affected device to reload. The vulnerability is due to a format string vulnerability when processing a crafted DHCP packet for Zero Touch Provisioning. An attacker could exploit this vulnerability by sending a specially crafted DHCP packet to an affected device. An exploit could allow the attacker to cause the device to reload, resulting in a denial of service (DoS) condition. This vulnerability affects Cisco ASR 920 Series Aggregation Services Routers that are running an affected release of Cisco IOS XE Software (3.13 through 3.18) and are listening on the DHCP server port. By default, the devices do not listen on the DHCP server port. Cisco Bug IDs: CSCuy56385.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Cisco IOS XE Software (ASR 920 Series Aggregation Services Routers)to a version that resolves this vulnerability.Fixed in 3.13 through 3.18 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Patch CSCuy56385 - Compensating control
Ensure the device is not listening on the DHCP server port (by default, Cisco ASR 920 Series Aggregation Services Routers do not listen on the DHCP server port).
Event History
Frequently Asked Questions
What is the severity of CVE-2017-3859?
CVE-2017-3859 has a high severity rating due to its potential to allow unauthenticated remote access leading to device reloads.
How do I fix CVE-2017-3859?
To fix CVE-2017-3859, upgrade your Cisco ASR 920 Series router to a version that is not affected by the vulnerability, as recommended by Cisco.
What devices are affected by CVE-2017-3859?
CVE-2017-3859 affects the Cisco ASR 920 Series routers running specific versions of IOS XE, particularly 3.13.4s through 3.18.3vs.
Can CVE-2017-3859 be exploited remotely?
Yes, CVE-2017-3859 can be exploited remotely by an unauthenticated attacker, making it critical to address.
What is the cause of CVE-2017-3859?
CVE-2017-3859 is caused by a format string vulnerability in the DHCP code related to the Zero Touch Provisioning feature.