The Tales of N4nj0

Micro Focus Network Automation - Open Redirect via Origin Header


I have found an unauthenticated Open Redirect via Origin Header on Micro Focus Network Automation versions 10.4x, 10.5x, 2018.05, 2018.11, 2019.05, 2020.02, 2020.08, 2020.11, 2021.05.

Product Information

Micro Focus Network Automation is a commercial software tool that automates network configuration and change management.
During a security audit of the product, I have found this issue.
Probably due to the number of impacted versions, this issue took the vendor 7 months to resolve.

Vulnerability Details

URL Redirection to Untrusted Site (‘Open Redirect’) - CWE-601

  • Summary: The Host HTTP parameter could cause the web application to redirect to the specified URL, when the requested endpoint is ‘/’. By modifying the URL value to a malicious site, an attacker may successfully launch a phishing scam and steal user credentials.
  • Prerequisites: None.
  • CVE and CVSS Score: CVE-2021-38123 | 6.1 (Medium)

Step-by-step instructions and PoC

The application presents an Open Redirect on the Host parameter, when the / endpoint is requested via an HTTP POST request.

Affected Endpoints

Below are the evidences with the vulnerability details and the payloads used.

The HTTP request is the following:

Cache-Control: no-cache
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Firefox/78.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
Origin: https://hostname
Connection: close
Referer: https://hostname/
Upgrade-Insecure-Requests: 1
Content-Type: application/x-www-form-urlencoded
Content-Length: 0

An attacker can send a link containing JavaScript code that allows a user who runs the code to be automatically redirected to a domain owned by the attacker himself.
The redirect is performed via the HTTP Location response header.

Open Redirect (1)

The victim is thus redirected to a malicious domain:

Open Redirect (2)

To perform this attack, the user does not need to be authenticated to the target application.

Security Impact

An attacker can construct a URL within the application that causes a redirection to an arbitrary external domain. This behavior can be leveraged to facilitate phishing attacks against users of the application. The ability to use an authentic application URL, targeting the correct domain and with a valid SSL certificate (if SSL is used), lends credibility to the phishing attack because many users, even if they verify these features, will not notice the subsequent redirection to a different domain.


  • 18/02/2021: First disclosure via e-mail to
  • Several times in the middle: Ping requests for status update (We’ve heard of a man, who heard another man…)
  • 07/09/2021: Published CVEs on MITRE.
  • 14/09/2021: NVD scored CVE-2021-38123 as 6.1 (Medium).