# CVE-2017-12373: Information disclosure in Cisco legacy ASA 5500 products TLS protocol implementation

> Remote attackers can decrypt captured TLS sessions on legacy Cisco ASA devices via a Bleichenbacher oracle attack, exposing sensitive data.

- **Severity:** Medium 5.9 (`CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/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:** 15 Dec 2017
- **Updated:** 5 Aug 2024
- **Also known as:** GHSA-3q2f-qcg5-6425

## What is CVE-2017-12373?

CVE-2017-12373 is a medium-severity vulnerability in Cisco legacy ASA 5500 products TLS protocol implementation, published on 15 Dec 2017. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A vulnerability in the TLS protocol implementation of legacy Cisco ASA 5500 Series (ASA 5505, 5510, 5520, 5540, and 5550) devices could allow an unauthenticated, remote attacker to access sensitive information, aka a Return of Bleichenbacher's Oracle Threat (ROBOT) attack. An attacker could iteratively query a server running a vulnerable TLS stack implementation to perform cryptanalytic operations that may allow decryption of previously captured TLS sessions. Cisco Bug IDs: CSCvg97652.

Weakness: CWE-203 (Observable Discrepancy), CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor)

## Which versions are affected by CVE-2017-12373?

It affects 5 products.


Products: Cisco Adaptive Security Appliance 5505 Firmware, Cisco Adaptive Security Appliance 5510 Firmware, Cisco Adaptive Security Appliance 5520 Firmware, Cisco Adaptive Security Appliance 5540 Firmware, Cisco Adaptive Security Appliance 5550 Firmware.

## How do I fix CVE-2017-12373?

No fix has been published for CVE-2017-12373 yet. Limit exposure of the affected software until one is available.

## Is CVE-2017-12373 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2017-12373 exists.

Public exploit code:

- Scanner for Bleichenbacher Oracle in RSA PKCS #1 v1.5 (metasploit)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2017-12373 and fix it if it is affected.

What it is: CVE-2017-12373 is a medium-severity vulnerability in Cisco legacy ASA 5500 products TLS protocol implementation, published on 15 Dec 2017. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2017-12373 exists.

Affected product: Cisco legacy ASA 5500 products TLS protocol implementation. 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-2017-12373/ (Markdown: https://insights.sbomify.com/CVE-2017-12373/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2017-12373
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2017-12373
- OSV: https://osv.dev/vulnerability/CVE-2017-12373

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From sbomify Insights: https://insights.sbomify.com/CVE-2017-12373/
Summaries are generated and may contain mistakes; the official description above is the record.