# CVE-2020-3564: Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software FTP Inspection Bypass Vulnerability

> An unauthenticated remote attacker can bypass FTP inspection on Cisco ASA and FTD devices by sending crafted traffic, allowing unauthorized FTP connections.

- **Severity:** Medium 5.8 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 21 Oct 2020
- **Updated:** 13 Nov 2024
- **Also known as:** GHSA-67g9-87g9-j8g9

## What is CVE-2020-3564?

CVE-2020-3564 is a medium-severity vulnerability in Cisco Adaptive Security Appliance, published on 21 Oct 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A vulnerability in the FTP inspection engine of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to bypass FTP inspection. The vulnerability is due to ineffective flow tracking of FTP traffic. An attacker could exploit this vulnerability by sending crafted FTP traffic through an affected device. A successful exploit could allow the attacker to bypass FTP inspection and successfully complete FTP connections.

Weakness: CWE-436 (Interpretation Conflict), CWE-284 (Improper Access Control)

## Which versions are affected by CVE-2020-3564?

It affects 3 products.


Products: Cisco Adaptive Security Appliance, Cisco Adaptive Security Appliance Software, Cisco Secure Firewall Threat Defense.

## How do I fix CVE-2020-3564?

No fix has been published for CVE-2020-3564 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-3564 being exploited?

There is no known exploitation of CVE-2020-3564 in the wild and no public exploit code.

## Other vulnerabilities in Cisco Adaptive Security Appliance

- [CVE-2021-1573](https://insights.sbomify.com/CVE-2021-1573/): Denial of service in Cisco Adaptive Security Appliance Software (high 8.6)
- [CVE-2021-34793](https://insights.sbomify.com/CVE-2021-34793/): Denial of service in Cisco Adaptive Security Appliance (ASA) Software (high 8.6)
- [CVE-2021-40117](https://insights.sbomify.com/CVE-2021-40117/): Denial of service in Cisco Adaptive Security Appliance (ASA) Software (high 8.6)
- [CVE-2021-40118](https://insights.sbomify.com/CVE-2021-40118/): Denial of service in Cisco Adaptive Security Appliance (ASA) Software (high 8.6)
- [CVE-2020-3304](https://insights.sbomify.com/CVE-2020-3304/): Denial of service in Cisco Adaptive Security Appliance (ASA) Software (high 8.6)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-3564 and fix it if it is affected.

What it is: CVE-2020-3564 is a medium-severity vulnerability in Cisco Adaptive Security Appliance, published on 21 Oct 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2020-3564 in the wild and no public exploit code.

Affected product: Cisco Adaptive Security Appliance. 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-2020-3564/ (Markdown: https://insights.sbomify.com/CVE-2020-3564/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-3564
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-3564
- OSV: https://osv.dev/vulnerability/CVE-2020-3564

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From sbomify Insights: https://insights.sbomify.com/CVE-2020-3564/
Summaries are generated and may contain mistakes; the official description above is the record.