Vulnerability · Published Sep 23, 2021 · Assigned by cisco

CVE-2021-1625Cisco IOS XE Software Zone-Based Policy Firewall ICMP and UDP Inspection Vulnerability

Medium 5.8

In plain English

A medium-severity improper access control in Cisco IOS XE Software from Cisco. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.9% (higher than 60% of all known vulnerabilities).

Severity (CVSS 3.1)5.8Medium

Exploit odds (30 days)0.9%top 39.9% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

A vulnerability in the Zone-Based Policy Firewall feature of Cisco IOS XE Software could allow an unauthenticated, remote attacker to prevent the Zone-Based Policy Firewall from correctly classifying traffic. This vulnerability exists because ICMP and UDP responder-to-initiator flows are not inspected when the Zone-Based Policy Firewall has either Unified Threat Defense (UTD) or Application Quality of Experience (AppQoE) configured. An attacker could exploit this vulnerability by attempting to send UDP or ICMP flows through the network. A successful exploit could allow the attacker to inject traffic through the Zone-Based Policy Firewall, resulting in traffic being dropped because it is incorrectly classified or in incorrect reporting figures being produced by high-speed logging (HSL).

Affected products (as reported)

Vendor	Product	Versions
Cisco	Cisco IOS XE Software	n/a

Weakness: CWE-284 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N

References

20210922 Cisco IOS XE Software Zone-Based Policy Firewall ICMP and UDP Inspection Vulnerability vendor-advisory, x_refsource_CISCO