---
title: "Retool security incident"
description: "What the retained public evidence establishes about the Retool 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/retool-security-incident-2023"
markdown_url: "https://www.ally.security/incidents/retool-security-incident-2023.md"
stix_url: "https://www.ally.security/incidents/retool-security-incident-2023/stix.json"
---

# Retool security incident

The retained public source describes the Retool incident as SMS phishing + deepfake voice call impersonating IT + MFA fatigue. Other material details remain unresolved.

Last modified Sep 19, 2026 · 1 source

## Summary

- **Environment:** Software/Dev tools
- **Operational impact:** The reviewed source does not establish a precise operational or data impact
- **Financial impact:** No financial figure is established by the reviewed source evidence

## What happened

In 2023, Retool experienced an incident in its software/dev tools environment. The retained source describes the attack path as follows: SMS phishing + deepfake voice call impersonating IT + MFA fatigue. [1](#source-1)

## Impact

- The reviewed source does not establish a precise affected-person count, data scope, or operational consequence.
- No financial loss, ransom amount, recovery cost, or regulatory penalty is established by the reviewed source evidence.

## Timeline

### September 13, 2023 — Documented public update

The [When MFA isn't actually MFA](https://retool.com/blog/mfa-isnt-mfa) 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: SMS phishing + deepfake voice call impersonating IT + MFA fatigue. The canonical record does not add intrusion steps beyond those supported by the source. [1](#source-1)

### Actors

- No threat actor group has been identified in the reviewed public evidence.

### TTPs

- [T1566 — Phishing](https://attack.mitre.org/techniques/T1566/) — mapped from the cited behavior. [1](#source-1)
- [T1621 — Multi-Factor Authentication Request Generation](https://attack.mitre.org/techniques/T1621/) — mapped from the cited behavior. [1](#source-1)

## Response

The retained source describes system restoration or operational recovery work. [1](#source-1)

This account is bounded to [When MFA isn't actually MFA](https://retool.com/blog/mfa-isnt-mfa). 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/retool-security-incident-2023/stix.json>)

## Sources

Primary source records used to research this incident.

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

### When MFA isn't actually MFA

research · Retool

<https://retool.com/blog/mfa-isnt-mfa>

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

Review the supporting structured claims.

1. **Affected Organization · 100% confidence · current**  
   Retool security incident: Retool
2. **Resulted In · 86% confidence · current**  
   Retool security incident: SMS phishing + deepfake voice call impersonating IT + MFA fatigue.
3. **Resulted In · 100% confidence · current**  
   Retool security incident: The reviewed source documents the retool security incident involving Retool.
4. **Used Attack Technique · 90% confidence · current**  
   Retool security incident: https://attack.mitre.org/techniques/T1566/
5. **Used Attack Technique · 90% confidence · current**  
   Retool security incident: https://attack.mitre.org/techniques/T1621/
6. **Occurred At · 100% confidence · current**  
   Documented public update: 2023-09-13
7. **Resulted In · 90% confidence · current**  
   Retool security incident: The retained source describes system restoration or operational recovery work.

</details>