Cisco IOS and IOS XE Software Smart Install Remote Code Execution Vulnerability
TL;DR 📌
A critical vulnerability in the Smart Install feature of Cisco IOS and IOS XE Software allows unauthenticated remote attackers to execute arbitrary code or trigger a denial of service on affected devices. Immediate action is required to mitigate risks.
What happened 🕵️♂️
Cisco has identified a vulnerability in the Smart Install feature of its IOS and IOS XE Software. This flaw allows an unauthenticated remote attacker to send crafted messages to devices, potentially leading to a buffer overflow. Successful exploitation can result in device reloads, arbitrary code execution, or an indefinite loop causing a watchdog crash. Cisco has observed ongoing exploitation attempts and strongly recommends upgrading to fixed software releases.
Affected products 🖥️
The vulnerability affects Cisco devices running vulnerable releases of Cisco IOS or IOS XE Software with the Smart Install client feature enabled. Devices configured as Smart Install directors are not affected. For specific device details, refer to the Smart Install Configuration Guide.
Fixed software 🔧
Upgrade to the first fixed release in your train (or later):
| Release / Product | First Fixed Release | Notes |
|---|---|---|
| 1.9 | Updated information about continued exploitation activity. | |
| 1.8 | Updated exploitation information. | |
| 1.7 | Updated metadata - Cisco Catalyst 6500 and 6800 Series Switches have been identified as not vulnerable, which resulted in fewer releases being vulnerable. Updated the IOS Software Checker accordingly. | |
| 1.6 | Updated IOS Software Checker with products found to be vulnerable. | |
| 1.5 | Updated IOS Software Checker with products found to be non-vulnerable. | |
| 1.4 | Emphasized that Smart Install is enabled by default. Added a link to the list of devices that support Smart Install. | |
| 1.3 | Added more details to the Workarounds section. | |
| 1.2 | Metadata update. | |
| 1.1 | Added the researcher’s company name. | |
| 1.0 | Initial public release. |
Workarounds 🧯
There are no workarounds that address this vulnerability for customers who require Cisco Smart Install. However, if Smart Install is not needed, it can be disabled using the no vstack command.
Risk in context 🎯
With a CVSS score of 9.8, this vulnerability is rated as Critical. The exposure is significant as it allows unauthenticated access, and the potential for denial of service or arbitrary code execution poses a serious risk to network integrity and availability.
Fast facts ⚡
- CVSS Score: 9.8 (Critical)
- Exploitation: Ongoing attempts observed
- Impact: Denial of service, arbitrary code execution
- Smart Install: Enabled by default on vulnerable devices
For leadership 🧭
This vulnerability presents a Critical risk to our network infrastructure due to its high CVSS score of 9.8. The exposure is concerning as it allows unauthenticated remote access, which could lead to denial of service or arbitrary code execution. Immediate remediation is necessary; we recommend patching affected devices within 7 days.
Operationally, the patching process should involve a brief maintenance window with no expected configuration drift.
Now: Assess affected devices and initiate patching.
Next: Monitor for any signs of exploitation.
Later: Review network configurations to ensure Smart Install is only enabled where necessary.
Please prioritize this issue to safeguard our network against potential exploitation.