Nessus Cross-site Scripting

Nessus 8.10.0 and earlier were found to contain a Stored XSS vulnerability due to improper validation of input during scan configuration. An authenticated, remote attacker could potentially exploit this vulnerability to execute arbitrary code in a user's session. Tenable has implemented additional input validation mechanisms to correct this issue in Nessus 8.11.0. (2020-07-15, CVE-2020-5765)

Content Injection vulnerability in Tenable Nessus prior to 8.5.0 may allow an authenticated, local attacker to exploit this vulnerability by convincing another targeted Nessus user to view a malicious URL and use Nessus to send fraudulent messages. Successful exploitation could allow the authenticated adversary to inject arbitrary text into the feed status, which will remain saved post session expiration. (2019-07-01, CVE-2019-3962)

Nessus versions 8.4.0 and earlier were found to contain a reflected XSS vulnerability due to improper validation of user-supplied input. An unauthenticated, remote attacker could potentially exploit this vulnerability via a specially crafted request to execute arbitrary script code in a users browser session. (2019-06-25, CVE-2019-3961)

Nessus versions 8.2.1 and earlier were found to contain a stored XSS vulnerability due to improper validation of user-supplied input. An authenticated, remote attacker could potentially exploit this vulnerability via a specially crafted request to execute arbitrary script code in a user's browser session. Tenable has released Nessus 8.2.2 to address this issue. (2019-02-12, CVE-2019-3923)

In Nessus before 7.1.0, a XSS vulnerability exists due to improper input validation. A remote authenticated attacker could create and upload a .nessus file, which may be viewed by an administrator allowing for the execution of arbitrary script code in a user's browser session. In other scenarios, XSS could also occur by altering variables from the Advanced Settings. (2018-05-18, CVE-2018-1147)

Cross site scripting is an attack where a web page executes code that is injected by an adversary. It usually appears, when users input is presented. This attack can be used to impersonate a user, take over control of the session, or even steal API keys.

The attack can be executed e.g. when you application injects the request parameter directly into the HTML code of the page returned to the user:

https://server.com/confirmation?message=Transaction+Complete

what results in:

<span>Confirmation: Transaction Complete</span>

In that case the message can be modified to become a valid Javascript code, e.g.:

https://server.com/confirmation?message=<script>dangerous javascript code here</script>

and it will be executed locally by the user's browser with full access to the user's personal application/browser data:

<span>Confirmation: <script>dangerous javascript code here</script></span>