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

# British Library security incident

Rhysida ransomware. Months-long systems outage; data auctioned on dark web.

Last modified Sep 19, 2026 · 1 source

## Summary

- **Environment:** Cultural/Government
- **Operational impact:** Months-long systems outage; data auctioned on dark web
- **Financial impact:** £6-7M recovery

## What happened

In 2023, British Library experienced an incident in its cultural/government environment. The retained source describes the attack path as follows: Rhysida ransomware. [1](#source-1)

The documented consequence was: Months-long systems outage; data auctioned on dark web. [1](#source-1)

## Impact

- Documented impact: Months-long systems outage; data auctioned on dark web. [1](#source-1)
- Documented financial consequence: £6-7M recovery. [1](#source-1)

## Threat Group & Attack Vector

The retained source describes the attack path as follows: Rhysida ransomware. The canonical record does not add intrusion steps beyond those supported by the source. [1](#source-1)

### Actors

- **Rhysida** — 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

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

This account is bounded to [Learning Lessons from the Cyber-Attack](https://www.bl.uk/files/v5dwkion/production/99206a2d1e9f07b35712b78f7d75fbb09560c08d.pdf/british-library-cyber-incident-review-8-march-2024.pdf?dl=). 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/british-library-security-incident-2023/stix.json>)

## Sources

Primary source records used to research this incident.

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

### Learning Lessons from the Cyber-Attack

official · British Library

<https://www.bl.uk/files/v5dwkion/production/99206a2d1e9f07b35712b78f7d75fbb09560c08d.pdf/british-library-cyber-incident-review-8-march-2024.pdf?dl=>

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

Review the supporting structured claims.

1. **Affected Organization · 100% confidence · current**  
   British Library security incident: British Library
2. **Resulted In · 95% confidence · current**  
   British Library security incident: £6-7M recovery.
3. **Used Attack Technique · 90% confidence · current**  
   British Library security incident: https://attack.mitre.org/techniques/T1486/
4. **Resulted In · 90% confidence · current**  
   British Library security incident: The retained source describes system restoration or operational recovery work.
5. **Resulted In · 100% confidence · current**  
   British Library security incident: The reviewed source documents the british library security incident involving British Library.
6. **Resulted In · 86% confidence · current**  
   British Library security incident: Months-long systems outage; data auctioned on dark web.
7. **Resulted In · 95% confidence · current**  
   British Library security incident: Rhysida ransomware.

</details>