Rule Category

SERVER-APACHE -- Snort has detected traffic exploiting vulnerabilities in Apache servers.

Alert Message

SERVER-APACHE Apache mod_http2 NULL pointer dereference attempt

Rule Explanation

This event is generated when an attacker attempts to exploit a NULL pointer dereference in Apache's HTTP2 handling. Impact: Detection of a Denial of Service Attack Details: Rule checks for an attempt to exploit a NULL pointer dereference vulnerability present in Apache's mod_http2. Ease of Attack: Simple

What To Look For

This rule alerts when an attempt to cause a denial of service condition during an http2 upgrade is detected.

Known Usage

No public information

False Positives

No known false positives


Cisco Talos Intelligence Group

MITRE ATT&CK Framework

Tactic: Impact

Technique: Network Denial of Service

For reference, see the MITRE ATT&CK vulnerability types here:


Rule Vulnerability

CVE Additional Information

A maliciously constructed HTTP/2 request could cause mod_http2 2.4.24, 2.4.25 to dereference a NULL pointer and crash the server process.
Severity Base Score7.5
Impact Score3.6 Exploit Score3.9
Confidentiality ImpactNONE Integrity ImpactNONE
Availability ImpactHIGH Access Vector
Authentication Ease of Access