---
title: "Colonial Pipeline security incident"
description: "What the retained public evidence establishes about the Colonial Pipeline incident, its attack path, impact, and response."
incident_type: "Cybersecurity incident"
status: "active"
last_modified: "2026-09-19"
canonical_url: "https://www.ally.security/incidents/colonial-pipeline-security-incident-2021"
markdown_url: "https://www.ally.security/incidents/colonial-pipeline-security-incident-2021.md"
stix_url: "https://www.ally.security/incidents/colonial-pipeline-security-incident-2021/stix.json"
---

# Colonial Pipeline security incident

DarkSide carried out a ransomware attack against Colonial Pipeline. Colonial Pipeline paid a ransom, and the U.S. Department of Justice later recaptured the majority of that payment.

Last modified Sep 19, 2026 · 1 source

## Summary

- **Environment:** Energy/Pipeline
- **Operational impact:** Colonial Pipeline paid a ransom, and the U.S. Department of Justice later recaptured the majority of that payment.
- **Financial impact:** No financial figure is established by the reviewed source evidence

## What happened

In 2021, Colonial Pipeline experienced an incident in its energy/pipeline environment. The retained source describes the attack path as follows: DarkSide carried out a ransomware attack against Colonial Pipeline. [1](#source-1)

The documented consequence was: Colonial Pipeline paid a ransom, and the U.S. Department of Justice later recaptured the majority of that payment. [1](#source-1)

## Impact

- Documented impact: Colonial Pipeline paid a ransom, and the U.S. Department of Justice later recaptured the majority of that payment. [1](#source-1)
- No financial loss, ransom amount, recovery cost, or regulatory penalty is established by the reviewed source evidence.

## Timeline

### June 7, 2021 — Documented public update

The [DAG Monaco Delivers Remarks at Press Conference on DarkSide Attack on Colonial Pipeline](https://www.justice.gov/archives/opa/speech/dag-monaco-delivers-remarks-press-conference-darkside-attack-colonial-pipeline) records the incident facts used in this briefing. [1](#source-1)

### September 19, 2026 — Briefing updated

This briefing was last reviewed and updated on September 19, 2026.

## Threat Group & Attack Vector

The retained source describes the attack path as follows: DarkSide carried out a ransomware attack against Colonial Pipeline. The canonical record does not add intrusion steps beyond those supported by the source. [1](#source-1)

### Actors

- **DarkSide** — identified in the supported attack description. [1](#source-1)

### TTPs

- [T1486 — Data Encrypted for Impact](https://attack.mitre.org/techniques/T1486/) — mapped from the cited behavior. [1](#source-1)

## Response

Colonial Pipeline quickly notified law enforcement, enabling the FBI and Justice Department to trace and seize cryptocurrency ransom proceeds. [1](#source-1)

This account is bounded to [DAG Monaco Delivers Remarks at Press Conference on DarkSide Attack on Colonial Pipeline](https://www.justice.gov/archives/opa/speech/dag-monaco-delivers-remarks-press-conference-darkside-attack-colonial-pipeline). Details absent from that evidence are left unresolved rather than inferred. [1](#source-1)

## Assets

[Download the case-scoped STIX 2.1 bundle](<https://www.ally.security/incidents/colonial-pipeline-security-incident-2021/stix.json>)

## Sources

Primary source records used to research this incident.

<a id="source-1"></a>

### DAG Monaco Delivers Remarks at Press Conference on DarkSide Attack on Colonial Pipeline

official · United States Department of Justice

<https://www.justice.gov/archives/opa/speech/dag-monaco-delivers-remarks-press-conference-darkside-attack-colonial-pipeline>

<details>
<summary>Evidence ledger</summary>

Review the supporting structured claims.

1. **Occurred At · 100% confidence · current**  
   Documented public update: 2021-06-07
2. **Resulted In · 95% confidence · current**  
   Colonial Pipeline security incident: DarkSide carried out a ransomware attack against Colonial Pipeline.
3. **Resulted In · 95% confidence · current**  
   Colonial Pipeline security incident: Colonial Pipeline quickly notified law enforcement, enabling the FBI and Justice Department to trace and seize cryptocurrency ransom proceeds.
4. **Used Attack Technique · 90% confidence · current**  
   Colonial Pipeline security incident: https://attack.mitre.org/techniques/T1486/
5. **Resulted In · 100% confidence · current**  
   Colonial Pipeline security incident: The reviewed source documents the colonial pipeline security incident involving Colonial Pipeline.
6. **Affected Organization · 100% confidence · current**  
   Colonial Pipeline security incident: Colonial Pipeline
7. **Resulted In · 95% confidence · current**  
   Colonial Pipeline security incident: Colonial Pipeline paid a ransom, and the U.S. Department of Justice later recaptured the majority of that payment.

</details>