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MITRE ATT&CK® Technique

T1499.001: OS Exhaustion Flood

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.[1] 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.[2]

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.[3]

EnterpriseT1499.001Sub-techniqueObject v1.2Modified
Discuss defensive coverageBack to ATT&CK
Glexia's Take · Automated analysis

Security context for executives and security teams

Automation confidenceMedium

T1499.001: OS Exhaustion Flood describes 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 fl...

Executive priority

T1499.001: OS Exhaustion Flood is an official MITRE ATT&CK technique. Glexia treats it as defensive behavior context for prioritizing monitoring, control validation, and response planning without using the object by itself as an attribution claim.

Technical view

Security teams should validate T1499.001: OS Exhaustion Flood by reviewing the official ATT&CK relationships, mapped tactics (impact), supported platforms (Linux, macOS, Windows), and available local telemetry before making detection or mitigation decisions.

Likely telemetry

  • Official ATT&CK relationships and object metadata
  • Network, endpoint, and security-tool telemetry

Detection direction

  • Validate whether T1499.001: OS Exhaustion Flood appears in your detection coverage and tabletop scenarios.
  • Use the object to align executive risk language with SOC, incident response, and detection engineering work.
  • Do not treat ATT&CK relationship context as attribution without corroborating evidence.

Mitigation priorities

  • Map the object to existing controls and identify missing telemetry or response ownership.
  • Prioritize mitigations that reduce exposure on the listed platforms and tactics.
  • Review adjacent ATT&CK relationships before changing policy, detections, or reporting language.
Additional notes and limits

Baseline Glexia take generated from the official MITRE ATT&CK STIX object, source hash, tactics, platforms, and detection fields. It is safe to replace with a richer model-generated take for the same source hash later.

This baseline take is source-grounded and schema-validated, but it does not include environment-specific telemetry, incident evidence, or threat-intelligence corroboration.

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Official MITRE ATT&CK definition

OS Exhaustion Flood

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.[1] 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.[2]

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.[3]

View the same entry on attack.mitre.org (MITRE-hosted reference; in-page links above use the Glexia ATT&CK library.)

Glexia analysis

How security teams should use this page

Treat this object as behavior context, not an attribution claim. Validate the related groups, software, data sources, and mitigations against official ATT&CK relationships and your own telemetry before making control-coverage decisions.

ATT&CK relationship table

Related techniques

This mirrors the MITRE pattern of making group, software, campaign, and technique relationships scannable. Relationship notes come from mirrored ATT&CK relationship text when available.

1 rows
DomainIDNameRelationship / procedure
EnterpriseT1499Endpoint Denial of ServiceThis object subtechnique of Endpoint Denial of Service.
Relationship explorer

All related ATT&CK context

mitigates · MitigationM1037: Filter Network TrafficEnterprisesubtechnique of · TechniqueT1499: Endpoint Denial of ServiceEnterprisedetects · Detection StrategyDET0356: Endpoint DoS via OS Exhaustion Flood Detection StrategyEnterprise
Mitigations

Mitigation direction

MitigationEnterprise

M1037: Filter Network Traffic

Employ network appliances and endpoint software to filter ingress, egress, and lateral network traffic. This includes protocol-based filtering, enforcing firewall rules, and blocking or restricting traffic based on predefined conditions to limit adversary movement and data exfiltration. This mitigation can be implemented through the following measures:

Ingress Traffic Filtering:

- Use Case: Configure network firewalls to allow traffic only from authorized IP addresses to public-facing servers. - Implementation: Limit SSH (port 22) and RDP (port 3389) traffic to specific IP ranges.

Egress Traffic Filtering:

- Use Case: Use firewalls or endpoint security software to block unauthorized outbound traffic to prevent data exfiltration and command-and-control (C2) communications. - Implementation: Block outbound traffic to known malicious IPs or regions where communication is unexpected.

Protocol-Based Filtering:

- Use Case: Restrict the use of specific protocols that are commonly abused by adversaries, such as SMB, RPC, or Telnet, based on business needs. - Implementation: Disable SMBv1 on endpoints to prevent exploits like EternalBlue.

Network Segmentation:

- Use Case: Create network segments for critical systems and restrict communication between segments unless explicitly authorized. - Implementation: Implement VLANs to isolate IoT devices or guest networks from core business systems.

Application Layer Filtering:

- Use Case: Use proxy servers or Web Application Firewalls (WAFs) to inspect and block malicious HTTP/S traffic. - Implementation: Configure a WAF to block SQL injection attempts or other web application exploitation techniques.

Change history

Object version and sync metadata

The fields below describe the current mirrored snapshot. When Glexia retains multiple ATT&CK source imports, you can open the table to compare the same object across releases (hashes and MITRE timestamps). For MITRE’s own release notes and roadmap, see ATT&CK resources — Updates.

ATT&CK release
19.2
Object version
1.2
Created
Modified
Raw hash
26735df4772f03b0...
Imported snapshots across ATT&CK releases(2)
ReleaseBundle importedObject versionModifiedStatusRaw hash
19.21.2Current bundle26735df4772f…
19.11.2Older bundle26735df4772f…
Raw source

Mirrored ATT&CK source object

The raw object is retained through the mirrored ATT&CK source bundle and object hash. The raw endpoint returns the exact object from the mirrored bundle when available.

Open mirrored raw JSONOpen MITRE-hosted copy
Source references

External references and citations

MITRE external references are preserved separately from Glexia analysis so citations remain traceable to their original source records.

  1. [1]
    Arbor AnnualDoSreport Jan 2018

    Philippe Alcoy, Steinthor Bjarnason, Paul Bowen, C.F. Chui, Kirill Kasavchnko, and Gary Sockrider of Netscout Arbor. (2018, January). Insight into the Global Threat Landscape - Netscout Arbor's 13th Annual Worldwide Infrastructure Security Report. Retrieved April 22, 2019.

    Open source URL
  2. [2]
    Cloudflare SynFlood

    Cloudflare. (n.d.). What is a SYN flood attack?. Retrieved April 22, 2019.

    Open source URL
  3. [3]
    Corero SYN-ACKflood

    Corero. (n.d.). What is a SYN-ACK Flood Attack?. Retrieved November 17, 2024.

    Open source URL
  4. [4]
    Cisco DoSdetectNetflow

    Cisco. (n.d.). Detecting and Analyzing Network Threats With NetFlow. Retrieved April 25, 2019.

    Open source URL
  5. [5]
    mitre-attackT1499.001
    Open source URL
Source and licensing

Source: MITRE ATT&CK®. © 2026 The MITRE Corporation. This work is reproduced and distributed with the permission of The MITRE Corporation. MITRE ATT&CK and ATT&CK are registered trademarks of The MITRE Corporation. Glexia is not affiliated with or endorsed by MITRE.

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