T1499.001 OS Exhaustion Flood Mappings

Adversaries may launch a denial of service (DoS) attack targeting an endpoint's operating system (OS). A system's OS is responsible for managing the finite resources as well as preventing the entire system from being overwhelmed by excessive demands on its capacity. These attacks do not need to exhaust the actual resources on a system; the attacks may simply exhaust the limits and available resources that an OS self-imposes.

Different ways to achieve this exist, including TCP state-exhaustion attacks such as SYN floods and ACK floods.(Citation: Arbor AnnualDoSreport Jan 2018) With SYN floods, excessive amounts of SYN packets are sent, but the 3-way TCP handshake is never completed. Because each OS has a maximum number of concurrent TCP connections that it will allow, this can quickly exhaust the ability of the system to receive new requests for TCP connections, thus preventing access to any TCP service provided by the server.(Citation: Cloudflare SynFlood)

ACK floods leverage the stateful nature of the TCP protocol. A flood of ACK packets are sent to the target. This forces the OS to search its state table for a related TCP connection that has already been established. Because the ACK packets are for connections that do not exist, the OS will have to search the entire state table to confirm that no match exists. When it is necessary to do this for a large flood of packets, the computational requirements can cause the server to become sluggish and/or unresponsive, due to the work it must do to eliminate the rogue ACK packets. This greatly reduces the resources available for providing the targeted service.(Citation: Corero SYN-ACKflood)

View in MITRE ATT&CK®

VERIS Mappings

Capability ID Capability Description Mapping Type ATT&CK ID ATT&CK Name Notes
action.hacking.variety.DoS Denial of service related-to T1499.001 Endpoint Denial of Service: OS Exhaustion Flood
action.malware.variety.DoS DoS attack related-to T1499.001 Endpoint Denial of Service: OS Exhaustion Flood
attribute.availability.variety.Degradation Performance degradation related-to T1499.001 Endpoint Denial of Service: OS Exhaustion Flood
attribute.availability.variety.Loss Loss related-to T1499.001 Endpoint Denial of Service: OS Exhaustion Flood

AWS Mappings

Capability ID Capability Description Mapping Type ATT&CK ID ATT&CK Name Notes
amazon_virtual_private_cloud Amazon Virtual Private Cloud technique_scores T1499.001 OS Exhaustion Flood
Comments
VPC security groups and network access control lists (NACLs) can be used to restrict access to endpoints but will prove effective at mitigating only low-end DOS attacks resulting in a Minimal score.
References
    aws_config AWS Config technique_scores T1499.001 OS Exhaustion Flood
    Comments
    The "elb-cross-zone-load-balancing-enabled" managed rule can verify that load balancing is properly configured, which can mitigate adversaries' ability to perform Denial of Service (DoS) attacks and impact resource availability. "cloudfront-origin-failover-enabled" can verify that failover policies are in place to increase CloudFront content availability. Coverage factor is minimal for these rules, since they are specific to a subset of the available AWS services, resulting in an overall score of Minimal.
    References
      aws_network_firewall AWS Network Firewall technique_scores T1499.001 OS Exhaustion Flood
      Comments
      AWS Network Firewall has the ability to pass, drop, or alert on traffic based on the network protocol as well as perform deep packet inspection on the payload. This functionality can be used to block adversaries from carrying out denial of service attacks by implementing restrictions on which IP addresses and domains can access the resources (e.g., allow lists) as well as which protocol traffic is permitted. That is, the AWS Network Firewall could block the source of the denial of service attack. This mapping is given a score of Partial because the source of the attack would have to be known before rules could be put in place to protect against it.
      References
        aws_shield AWS Shield technique_scores T1499.001 OS Exhaustion Flood
        Comments
        AWS Shield Standard provides protection and response to these Denial of Service attacks in real time by using a network traffic baseline and identifying anomalies among other techniques.
        References