CVE-2023-20033

8.6 HIGH

📋 TL;DR

This vulnerability in Cisco Catalyst 3650 and 3850 Series Switches running IOS XE allows unauthenticated remote attackers to cause a denial of service by sending high-rate traffic to the management interface, forcing the device to reload. It affects organizations using these specific switch models with vulnerable IOS XE versions.

💻 Affected Systems

Products:
  • Cisco Catalyst 3650 Series Switches
  • Cisco Catalyst 3850 Series Switches
Versions: IOS XE Software releases prior to 17.9.4, 17.10.1, and 17.11.1
Operating Systems: Cisco IOS XE
Default Config Vulnerable: ⚠️ Yes
Notes: Only affects traffic received on the management interface (GigabitEthernet0/0). Data plane interfaces are not vulnerable.

📦 What is this software?

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

Ios Xe by Cisco

Cisco IOS XE is Cisco's modern network operating system running on enterprise routers, switches, and wireless controllers deployed across corporate networks, data centers, branch offices, and service provider infrastructure worldwide. As the evolution of Cisco IOS, IOS XE provides a Linux-based modu...

Learn more about Ios Xe →

⚠️ Risk & Real-World Impact

🔴

Worst Case

Complete network outage affecting all services running through the switch, requiring manual reboot and potentially causing extended downtime.

🟠

Likely Case

Intermittent network disruptions and service degradation as switches reload, impacting business operations until patched.

🟢

If Mitigated

Minimal impact if management interfaces are properly firewalled and rate-limited, with only authorized traffic reaching the vulnerable interface.

🌐 Internet-Facing: HIGH if management interface is exposed to internet, as unauthenticated attackers can easily trigger DoS.
🏢 Internal Only: MEDIUM if management interface is accessible on internal network, requiring attacker to have internal access but no authentication.

🎯 Exploit Status

Public PoC: ✅ No
Weaponized: LIKELY
Unauthenticated Exploit: ⚠️ Yes
Complexity: LOW

Exploitation requires only sending high-rate traffic to management interface, making it trivial for attackers with network access.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: IOS XE 17.9.4, 17.10.1, or 17.11.1 and later

Vendor Advisory: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-cat3k-dos-ZZA4Gb3r

Restart Required: Yes

Instructions:

1. Download appropriate fixed software version from Cisco.com. 2. Backup current configuration. 3. Upgrade IOS XE software following Cisco's upgrade procedures. 4. Reload switch to apply new version.

🔧 Temporary Workarounds

Restrict Management Interface Access

all

Apply access control lists to limit traffic to management interface to trusted sources only.

ip access-list extended MGMT-ACL
permit ip trusted-source any
deny ip any any
interface GigabitEthernet0/0
ip access-group MGMT-ACL in

Rate Limit Management Interface Traffic

all

Apply rate limiting to management interface to prevent high-rate traffic attacks.

interface GigabitEthernet0/0
rate-limit input 8000 1500 3000 conform-action transmit exceed-action drop

🧯 If You Can't Patch

  • Implement strict network segmentation to isolate management interfaces from untrusted networks
  • Deploy intrusion prevention systems to detect and block high-rate traffic patterns to management interfaces

🔍 How to Verify

Check if Vulnerable:

Check IOS XE version with 'show version' command and compare to vulnerable releases (prior to 17.9.4, 17.10.1, 17.11.1).

Check Version:

show version | include Version

Verify Fix Applied:

Verify upgraded version with 'show version' command shows 17.9.4, 17.10.1, 17.11.1 or later.

📡 Detection & Monitoring

Log Indicators:

  • Unexpected switch reloads
  • High CPU utilization on management interface
  • Interface resets on GigabitEthernet0/0

Network Indicators:

  • High traffic volume to switch management IP addresses
  • Unusual traffic patterns to UDP/TCP ports on management interface

SIEM Query:

source="catalyst-switch" ("reload" OR "%SYS-5-RESTART" OR "%CPUHOG")

🔗 References

📤 Share & Export