Rule Category

SERVER-WEBAPP -- Snort has detected traffic exploiting vulnerabilities in web based applications on servers.

Alert Message

SERVER-WEBAPP Apache Server mod_proxy Error Page cross site scripting attempt

Rule Explanation

Apache HTTP Server versions 2.4.0-2.4.39 are vulnerable to a limited cross-site scripting attack via a mod_proxy error page.

What To Look For

This rule will alert when an attempt is made to trigger a Cross-Site Scripting vulnerability on an Apache HTTP server running mod_proxy.

Known Usage

Public information/Proof of Concept available

False Positives

No known false positives

Contributors

Cisco Talos Intelligence Group

MITRE ATT&CK Framework

Tactic: Execution

Technique: User Execution

For reference, see the MITRE ATT&CK vulnerability types here: https://attack.mitre.org

CVE

Rule Vulnerability

Cross Site Scripting (XSS)

Cross Site Scripting (XSS) attackers send malicious input to a site that does not validate the input, usually in the form of a script. The application sends the malicious code to the browsers of other users, which will execute the script unknowingly. The malicious code uses the trust of the host website to access cookies, session tokens, or other sensitive information. There are multiple types of XSS, including Stored, Reflected, and DOM based.

CVE Additional Information

CVE-2019-10092
In Apache HTTP Server 2.4.0-2.4.39, a limited cross-site scripting issue was reported affecting the mod_proxy error page. An attacker could cause the link on the error page to be malformed and instead point to a page of their choice. This would only be exploitable where a server was set up with proxying enabled but was misconfigured in such a way that the Proxy Error page was displayed.
Details
SeverityMEDIUM Base Score4.3
Impact Score2.9 Exploit Score8.6
Confidentiality ImpactNONE Integrity ImpactPARTIAL
Availability ImpactNONE Access VectorNETWORK
AuthenticationNONE Ease of AccessMEDIUM