# CVE-2022-20767: Cisco Firepower Threat Defense Software DNS Enforcement Denial of Service Vulnerability

> Remote attackers can cause denial of service on Cisco FTD devices by sending crafted UDP packets, affecting devices running Snort 3.

- **Severity:** High 8.6 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 3 May 2022
- **Updated:** 6 Nov 2024
- **Also known as:** GHSA-6hf5-f728-cg27

## What is CVE-2022-20767?

CVE-2022-20767 is a high-severity denial of service vulnerability in Cisco Secure Firewall Threat Defense, published on 3 May 2022. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A vulnerability in the Snort rule evaluation function of Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to improper handling of the DNS reputation enforcement rule. An attacker could exploit this vulnerability by sending crafted UDP packets through an affected device to force a buildup of UDP connections. A successful exploit could allow the attacker to cause traffic that is going through the affected device to be dropped, resulting in a DoS condition. Note: This vulnerability only affects Cisco FTD devices that are running Snort 3.

Weakness: CWE-770 (Allocation of Resources Without Limits or Throttling), CWE-399

## Which versions are affected by CVE-2022-20767?

It affects 1 product.


Products: Cisco Secure Firewall Threat Defense.

## How do I fix CVE-2022-20767?

No fix has been published for CVE-2022-20767 yet. Limit exposure of the affected software until one is available.

## Is CVE-2022-20767 being exploited?

There is no known exploitation of CVE-2022-20767 in the wild and no public exploit code.

## Other vulnerabilities in Cisco Secure Firewall Threat Defense

- [CVE-2024-20412](https://insights.sbomify.com/CVE-2024-20412/): Hardcoded credentials in Cisco Firepower Threat Defense Software (critical 9.3)
- [CVE-2024-20330](https://insights.sbomify.com/CVE-2024-20330/): Memory corruption in Cisco Firepower Threat Defense Software (high 8.6)
- [CVE-2024-20339](https://insights.sbomify.com/CVE-2024-20339/): Cisco Firepower Threat Defense Software for Firepower 2100 Series TLS Denial of Service Vulnerability (high 8.6)
- [CVE-2024-20351](https://insights.sbomify.com/CVE-2024-20351/): Cisco Firepower Threat Defense Software Snort Firewall Denial of Service Vulnerability (high 8.6)
- [CVE-2023-20083](https://insights.sbomify.com/CVE-2023-20083/): Denial of service in Cisco Firepower Threat Defense Software (high 8.6)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2022-20767 and fix it if it is affected.

What it is: CVE-2022-20767 is a high-severity denial of service vulnerability in Cisco Secure Firewall Threat Defense, published on 3 May 2022. 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-2022-20767 in the wild and no public exploit code.

Affected product: Cisco Secure Firewall Threat Defense. 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-2022-20767/ (Markdown: https://insights.sbomify.com/CVE-2022-20767/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2022-20767
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2022-20767
- OSV: https://osv.dev/vulnerability/CVE-2022-20767

---
From sbomify Insights: https://insights.sbomify.com/CVE-2022-20767/
Summaries are generated and may contain mistakes; the official description above is the record.