SERVER-WEBAPP -- Snort has detected traffic exploiting vulnerabilities in web based applications on servers.
SERVER-WEBAPP Apache Tomcat HTTP/2 denial of service attempt
The rule looks for indication of multiple h2c upgrade attempts are made in succession, indicating a potential attempt to exhaust processor resources.
What To Look For
This rule fires upon attempted exploitation of CVE-2020-13934, a denial of service vulnerability of Apache Tomcat.
No public information
No known false positives
Cisco Talos Intelligence Group
MITRE ATT&CK Framework
Technique: Endpoint Denial of Service
For reference, see the MITRE ATT&CK vulnerability types here:
Denial of Service
Denial of Service attacks aim to make a server or program unresponsive for users. These attacks may be volume-based, to overwhelm the system, or they may use certain logical flaws in the software to cut the service off from the users. The attack may come from one or multiple sources. These attacks do not usually lead to a remote code execution. Volume based attacks are best handled using a firewall application.
CVE Additional Information
CVE-2020-13934An h2c direct connection to Apache Tomcat 10.0.0-M1 to 10.0.0-M6, 9.0.0.M5 to 9.0.36 and 8.5.1 to 8.5.56 did not release the HTTP/1.1 processor after the upgrade to HTTP/2. If a sufficient number of such requests were made, an OutOfMemoryException could occur leading to a denial of service.
||Ease of Access||LOW