Threat ActorHuman reviewed 2026-08-26 · FireEye
APT21
Tech
APT21 — Tech (China-linked) (Source: FireEye)
Definition
Espionage
Why It Matters / Profile
- Sponsorship: China
- Active since: 2010
- Aliases: Squirrel
Current Status
- Review status: published
- Last updated: 2026-08-26
- Evidence: 3 source(s) · 1 technique(s)
- Confidence: 85%
ATT&CK Techniques
Targets
- Tech
Timeline
- 2010 — APT21 activity first documented
- 2026-08-26 — Profile reviewed (Phase 45C)
Sources
Start Investigation
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- Question — what do you need to know about APT21?
- Evidence — assertions mapped to verifiable references.
- Timeline — events in chronological order.
- Related Entities — CVE, threat actor, campaign, malware links.
- Sources — NVD, CISA KEV, MITRE ATT&CK, vendor advisories.
- Notes — your own observations and working hypotheses.
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