# CVE-2001-0669: Security feature bypass in n/a

> Remote attackers can evade HTTP attack detection in various IDS products by using non-standard Unicode encoding in URLs.

- **Severity:** High 7.5 (`AV:N/AC:L/Au:N/C:P/I:P/A:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 12 Oct 2001
- **Updated:** 8 Aug 2024
- **Also known as:** GHSA-5xc8-p2x4-cp2p

## What is CVE-2001-0669?

CVE-2001-0669 is a high-severity vulnerability in n/a, published on 12 Oct 2001. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Various Intrusion Detection Systems (IDS) including (1) Cisco Secure Intrusion Detection System, (2) Cisco Catalyst 6000 Intrusion Detection System Module, (3) Dragon Sensor 4.x, (4) Snort before 1.8.1, (5) ISS RealSecure Network Sensor 5.x and 6.x before XPU 3.2, and (6) ISS RealSecure Server Sensor 5.5 and 6.0 for Windows, allow remote attackers to evade detection of HTTP attacks via non-standard "%u" Unicode encoding of ASCII characters in the requested URL.

## Which versions are affected by CVE-2001-0669?

It affects 6 products.


Products: Cisco Catalyst 6000 Intrusion Detection System Module, Cisco Secure Intrusion Detection System, Enterasys Dragon, Iss Realsecure Network Sensor, Iss Realsecure Server Sensor, Snort Snort.

## How do I fix CVE-2001-0669?

No fix has been published for CVE-2001-0669 yet. Limit exposure of the affected software until one is available.

## Is CVE-2001-0669 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2001-0669 exists.

Public exploit code:

- Cisco Secure IDS 2.0/3.0 / Snort 1.x / ISS RealSecure 5/6 / NFR 5.0 - Encoded IIS Detection Evasion (exploitdb)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2001-0669 and fix it if it is affected.

What it is: CVE-2001-0669 is a high-severity vulnerability in n/a, published on 12 Oct 2001. 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-2001-0669 exists.

Affected product: n/a. 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-2001-0669/ (Markdown: https://insights.sbomify.com/CVE-2001-0669/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2001-0669
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2001-0669
- OSV: https://osv.dev/vulnerability/CVE-2001-0669

---
From sbomify Insights: https://insights.sbomify.com/CVE-2001-0669/
Summaries are generated and may contain mistakes; the official description above is the record.