Case iwai-cosmo-securities-ai-attackAI-assisted malwareJapan
IwaiCosmo Securities hit by cyberattack on its trading system with unauthorized trades; AI suspected
IwaiCosmo Securities said a third party gained unauthorized access on 2026-10-14 to the trade management system run by Trade Works, which operates its online trading system. Unauthorized orders were placed in seven customer accounts and executed in five, and the personal data of 4,975 people leaked. Japanese media, including Kyodo, Nikkei and MBS, report that AI is suspected to have been used in the attack, but this is not confirmed. The company's chairman apologized on 2026-10-23.
MediumAttack using AIStatus: Under investigationVerified case file
Open in the interactive mapCite this case
- Reported
- Oct 21, 2026
- Location
- Japan
- Target
- IwaiCosmo Securities online trading system (operated by Trade Works)
- Severity
- Medium
- Verification
- Reported by credible press or researchers
- Triggered by
- Unidentified third party (alleged AI use)
- Actor type
- Unknown
- Sector
- Financial services
- Reported loss
- None reported
- CVE
- None
What happened
IwaiCosmo Securities said a third party gained unauthorized access on 2026-10-14 to the trade management system run by Trade Works, which operates its online trading system. Unauthorized orders were placed in seven customer accounts and executed in five, and the personal data of 4,975 people leaked. Japanese media, including Kyodo, Nikkei and MBS, report that AI is suspected to have been used in the attack, but this is not confirmed. The company's chairman apologized on 2026-10-23.
Impact: Unauthorized orders in 7 accounts, trades executed in 5; personal data of 4,975 individuals leaked
Who triggered it
Actor: Unidentified third party (alleged AI use)
Attribution: Unknown; the company only refers to an unnamed third party.
Motive: Unknown
How it happened
Attack vector: Unknown; the company says AI was used in the attack on its systems.
Root cause: Unknown
Timeline
- Reported by 共同网
Response
The company publicly disclosed the attack; no further response details were given.
Current status: Under investigation
Research warnings this case matches
- Seen in real incidents AI makes cyberattacks easier, faster and larger · CAIS
- Seen in real incidents Criminals and state hackers use AI in cyberattacks · International AI Safety Report
- Seen in real incidents Malicious actors and misuse · MIT AI Risk Repository
Compared with published AI risk research from several institutes on the Research vs reality page.
Sources (open in a new tab)
- 共同网 news.google.com
- Nikkei Asia asia.nikkei.com
- MBS News (Yahoo! Japan) news.yahoo.co.jp
Cite this case
IwaiCosmo Securities hit by cyberattack on its trading system with unauthorized trades; AI suspected. AI Threat Watch, case iwai-cosmo-securities-ai-attack, Oct 21, 2026. https://aithreat.io/cases/iwai-cosmo-securities-ai-attack/
Permanent link: https://aithreat.io/cases/iwai-cosmo-securities-ai-attack/
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