# CVE-2020-3524: Cisco IOS XE ROM Monitor Software Vulnerability

> Physical attackers can bypass secure boot by exploiting a debug option in ROMMON to load unsigned software images on Cisco routers.

- **Severity:** Medium 6.4 (`CVSS:3.0/AV:P/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 24 Sep 2020
- **Updated:** 13 Nov 2024
- **Also known as:** GHSA-wvf6-cqwc-cf6x

## What is CVE-2020-3524?

CVE-2020-3524 is a medium-severity vulnerability in Cisco IOS XE ROMMON Software, published on 24 Sep 2020. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A vulnerability in the Cisco IOS XE ROM Monitor (ROMMON) Software for Cisco 4000 Series Integrated Services Routers, Cisco ASR 920 Series Aggregation Services Routers, Cisco ASR 1000 Series Aggregation Services Routers, and Cisco cBR-8 Converged Broadband Routers could allow an unauthenticated, physical attacker to break the chain of trust and load a compromised software image on an affected device. The vulnerability is due to the presence of a debugging configuration option in the affected software. An attacker could exploit this vulnerability by connecting to an affected device through the console, forcing the device into ROMMON mode, and writing a malicious pattern using that specific option on the device. A successful exploit could allow the attacker to break the chain of trust and load a compromised software image on the affected device. A compromised software image is any software image that has not been digitally signed by Cisco.

Weakness: CWE-862 (Missing Authorization), CWE-284 (Improper Access Control)

## Which versions are affected by CVE-2020-3524?

It affects 1 product.


Products: Cisco Ios Xe Rom Monitor.

## How do I fix CVE-2020-3524?

No fix has been published for CVE-2020-3524 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-3524 being exploited?

There is no known exploitation of CVE-2020-3524 in the wild and no public exploit code.

## Other vulnerabilities in Cisco IOS XE ROMMON Software

- [CVE-2021-1452](https://insights.sbomify.com/CVE-2021-1452/): Cisco IOS XE ROM Monitor Software for Cisco Industrial Switches OS Command Injection Vulnerability (medium 6.8)
- [CVE-2022-20864](https://insights.sbomify.com/CVE-2022-20864/): Cisco IOS XE ROM Monitor Software for Catalyst Switches Information Disclosure Vulnerability (medium 4.6)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-3524 and fix it if it is affected.

What it is: CVE-2020-3524 is a medium-severity vulnerability in Cisco IOS XE ROMMON Software, published on 24 Sep 2020. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2020-3524 in the wild and no public exploit code.

Affected product: Cisco IOS XE ROMMON Software. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2020-3524/ (Markdown: https://insights.sbomify.com/CVE-2020-3524/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-3524
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-3524
- OSV: https://osv.dev/vulnerability/CVE-2020-3524

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-3524/
Summaries are generated and may contain mistakes; the official description above is the record.