Service Exhaustion Flood
Where this stands
A reviewer read the telemetry and concluded there is nothing here to detect that a sibling technique does not already cover.
Every analytic in the brief describes a rate, and none of the brief's log sources can carry a rate. AN0489's Windows sources are Sysmon EventID 3 (network_connection) and EventID 22 (dns_query): EID 3 emits one event per connection with no count, so the only field-level residue of an HTTP flood is 'Initiated: false' plus DestinationPort 80/443/8080, which every legitimate request to a web service also satisfies -- an always-true selection on any host that serves HTTP, precisely the silent failure this pipeline exists to avoid; EID 22 records the names the host itself resolved, so it observes the machine as a DNS client and structurally cannot see a flood aimed at a DNS service the machine hosts. […]
What the technique is
Adversaries may target the different network services provided by systems to conduct a denial of service (DoS). Adversaries often target the availability of DNS and web services, however others have been targeted as well. Web server software can be attacked through a variety of means, some of which apply generally while others are specific to the software being used to provide the service. One example of this type of attack is known as a simple HTTP flood, where an adversary sends a large number of HTTP requests to a web server to overwhelm it and/or an application that runs on top of it. This flood relies on raw volume to accomplish the objective, exhausting any of the various resources required by the victim software to provide the service. Another variation, known as a SSL renegotiation attack, takes advantage of a protocol feature in SSL/TLS. The SSL/TLS protocol suite includes mechanisms for the client and server to agree on an encryption algorithm to use for subsequent secure connections. If SSL renegotiation is enabled, a request can be made for renegotiation of the crypto algorithm. In a renegotiation attack, the adversary establishes a SSL/TLS connection and then proceeds to make a series of renegotiation requests. […]
Read it on attack.mitre.orgWhat MITRE says you would watch
- AN0489
High-frequency, repetitive service requests (e.g., HTTP, TLS renegotiation) originating from a single or small set of source IPs targeting endpoint web services or application ports, leading to exhaustion of CPU or memory on targeted Windows services.
- AN0490
Excessive inbound HTTP or TLS connections to services such as Apache or Nginx, causing worker thread exhaustion or segmentation faults.
- AN0491
Flood of incoming TLS or HTTP(S) connections to macOS-hosted services (e.g., MAMP, Apache), causing high CPU usage and system unresponsiveness.
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