# CVE-2020-3585: Cisco Firepower 1000 Series Bleichenbacher Attack Vulnerability

> An unauthenticated remote attacker can decrypt captured TLS sessions by exploiting a Bleichenbacher vulnerability in the TLS handler of Cisco Firepower 1000 Series devices.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/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-w7hv-422j-p88g

## What is CVE-2020-3585?

CVE-2020-3585 is a medium-severity vulnerability in Cisco Adaptive Security Appliance Software, 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 TLS handler of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software for Cisco Firepower 1000 Series firewalls could allow an unauthenticated, remote attacker to gain access to sensitive information. The vulnerability is due to improper implementation of countermeasures against the Bleichenbacher attack for cipher suites that rely on RSA for key exchange. An attacker could exploit this vulnerability by sending crafted TLS messages to the device, which would act as an oracle and allow the attacker to carry out a chosen-ciphertext attack. A successful exploit could allow the attacker to perform cryptanalytic operations that may allow decryption of previously captured TLS sessions to the affected device. To exploit this vulnerability, an attacker must be able to perform both of the following actions: Capture TLS traffic that is in transit between clients and the affected device Actively establish a considerable number of TLS connections to the affected device

Weakness: CWE-203 (Observable Discrepancy)

## Which versions are affected by CVE-2020-3585?

It affects 3 products.


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

## How do I fix CVE-2020-3585?

No fix has been published for CVE-2020-3585 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-3585 being exploited?

There is no known exploitation of CVE-2020-3585 in the wild and no public exploit code.

## Other vulnerabilities in Cisco Adaptive Security Appliance Software

- [CVE-2025-20333](https://insights.sbomify.com/CVE-2025-20333/): Cisco Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FTD) Buffer Overflow (critical 9.9, exploited in the wild)
- [CVE-2016-6366](https://insights.sbomify.com/CVE-2016-6366/): Cisco Adaptive Security Appliance (ASA) SNMP Buffer Overflow (high 8.8, exploited in the wild)
- [CVE-2026-20349](https://insights.sbomify.com/CVE-2026-20349/): Cisco Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FTD) Heap Inspection (high 8.6, exploited in the wild)
- [CVE-2024-20353](https://insights.sbomify.com/CVE-2024-20353/): Cisco ASA and FTD Denial of Service (high 8.6, exploited in the wild)
- [CVE-2016-6367](https://insights.sbomify.com/CVE-2016-6367/): Cisco Adaptive Security Appliance (ASA) CLI Remote Code Execution (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-3585 and fix it if it is affected.

What it is: CVE-2020-3585 is a medium-severity vulnerability in Cisco Adaptive Security Appliance Software, 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-2020-3585 in the wild and no public exploit code.

Affected product: Cisco Adaptive Security Appliance 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-2020-3585/ (Markdown: https://insights.sbomify.com/CVE-2020-3585/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-3585
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-3585
- OSV: https://osv.dev/vulnerability/CVE-2020-3585

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From sbomify Insights: https://insights.sbomify.com/CVE-2020-3585/
Summaries are generated and may contain mistakes; the official description above is the record.