Cisco IOS Software Industrial Ethernet Switch Device Manager Denial of Service Vulnerability

TL;DR 📌

A denial of service (DoS) vulnerability has been identified in the web UI of Cisco IOS Software for Industrial Ethernet Switches. An authenticated remote attacker with low privileges can exploit this vulnerability by sending a specially crafted URL, potentially causing the device to reload and become unavailable. Cisco has released software updates to address this issue, but there are no workarounds available.

What happened 🕵️‍♂️

A vulnerability in the web UI of Cisco IOS Software could allow an authenticated, remote attacker with low privileges to cause a denial of service (DoS) condition on affected devices. This vulnerability arises from improper input validation, enabling attackers to exploit it by sending a crafted URL in an HTTP request. A successful exploit could lead to the affected device reloading, resulting in a DoS condition.

Affected products 🖥️

The following Cisco Industrial Ethernet (IE) Series Switches are affected if they are running a vulnerable release of Cisco IOS Software and have the HTTP Server feature enabled:

• IE 2000 Series
• IE 3010 Series
• IE 4000 Series
• IE 4010 Series
• IE 5000 Series

To check if the HTTP Server feature is enabled, use the command: show running-config | include ip http server|secure|active.

Fixed software 🔧

Upgrade to the first fixed release in your train (or later):

Workarounds 🧯

There are no workarounds that directly address this vulnerability. However, a mitigation is available: disabling the HTTP Server feature will eliminate the attack vector. This can be done using the commands no ip http server or no ip http secure-server in global configuration mode. Both commands must be executed if both HTTP and HTTPS servers are enabled.

Risk in context 🎯

The vulnerability has a CVSS score of 7.7, indicating a High severity risk. The exposure is primarily driven by the requirement for authentication and the potential for denial of service. There is a risk of operational impact if the HTTP Server feature is disabled, but this is a necessary step until devices can be upgraded.

Fast facts ⚡

• Vulnerability: DoS in Cisco IOS Software web UI
• CVSS Score: 7.7 (High)
• Affected Products: IE 2000, 3010, 4000, 4010, and 5000 Series Switches
• Exploitation: Requires authenticated access
• Mitigation: Disable HTTP Server feature

For leadership 🧭

Executive summary. A flaw in the web management interface of Cisco Industrial Ethernet switches lets someone with only basic login access crash and reload the device, interrupting whatever network traffic depends on it. Because these switches are often used in plant or process control networks, an unplanned reload can mean a real operational outage, so this should be scheduled into the next maintenance window rather than deferred indefinitely.

Why it matters:

• Affects IE 2000, 3010, 4000, 4010 and 5000 Series switches when the HTTP or HTTPS server feature is enabled, which is common on devices managed via the web UI.
• An authenticated attacker with low privileges only needs to send one crafted URL in an HTTP request to trigger a full device reload.
• Industrial Ethernet switches typically sit in operational technology or plant networks, so a reload can disrupt control traffic, not just office connectivity.
• No workaround exists that leaves the web UI usable; the only mitigation is disabling the HTTP/HTTPS server, which removes remote GUI management until devices are patched.

Now / Next / Later:

• Now: Run show running-config | include ip http server|secure|active on every IE 2000/3010/4000/4010/5000 switch to identify which have the HTTP Server feature enabled and are therefore exposed.
• Next: During the next change window, upgrade affected switches to the first fixed Cisco IOS release for their train; where upgrading must wait, disable the web server with no ip http server and no ip http secure-server (both, if in use).
• Later: Review whether web-based management needs to stay enabled on industrial switches at all, and where it does, restrict access to trusted management networks and accounts with least-privilege login levels.