CVE-2017-12237: high-severity vulnerability in Cisco IOS and IOS XE
Published · Updated
51Vexday Risk Score
Prioritize patching. It under exploitation confirmed by CISA.
ssvc Actcvss 7.5epss 7.1%
from disclosure to weapon
Published on NVDSep 28
CISA KEV+1617d
exploitation probability
7.1%top 6% of all CVEs
observed exploitation
yesCISA + VulnCheck
Action required by CISAfederal deadline: 2022-03-24
Apply updates per vendor instructions.
In short
A flaw in Cisco IOS and IOS XE devices allows an attacker to send specially crafted network packets that overwhelm the device's processor or cause it to restart, disrupting network services. This happens when the device's security protocol (ISAKMP) is enabled, even if VPN features aren't actively configured.
Technical detail
The vulnerability exists in IKEv2 packet processing within Cisco IOS 15.0-15.6 and IOS XE 3.5-16.5. An unauthenticated remote attacker can send malformed IKEv2 packets to trigger excessive CPU consumption, system crashes, or device reloads, resulting in denial of service. Exploitation requires only network reachability to the affected device with ISAKMP enabled; no prior authentication or VPN configuration is necessary.
Summary generated and translated by AI from the official description.
A vulnerability in the Internet Key Exchange Version 2 (IKEv2) module of Cisco IOS 15.0 through 15.6 and Cisco IOS XE 3.5 through 16.5 could allow an unauthenticated, remote attacker to cause high CPU utilization, traceback messages, or a reload of an affected device that leads to a denial of service (DoS) condition. The vulnerability is due to how an affected device processes certain IKEv2 packets. An attacker could exploit this vulnerability by sending specific IKEv2 packets to an affected device to be processed. A successful exploit could allow the attacker to cause high CPU utilization, traceback messages, or a reload of the affected device that leads to a DoS condition. This vulnerability affects Cisco devices that have the Internet Security Association and Key Management Protocol (ISAKMP) enabled. Although only IKEv2 packets can be used to trigger this vulnerability, devices that are running Cisco IOS Software or Cisco IOS XE Software are vulnerable when ISAKMP is enabled. A device does not need to be configured with any IKEv2-specific features to be vulnerable. Many features use IKEv2, including different types of VPNs such as the following: LAN-to-LAN VPN; Remote-access VPN, excluding SSL VPN; Dynamic Multipoint VPN (DMVPN); and FlexVPN. Cisco Bug IDs: CSCvc41277.