The Breton banking group Crédit Mutuel Arkéa confirmed this Wednesday, November 4, that it had fallen victim to a cyberattack that enabled fraudulent operations.
While the institution insists that the incident is now under control and has no financial impact on its customers, it has not officially disclosed the amount of the damage, estimated at around €118 million.
The matter was first brought to light by ZachXBT, an independent investigator known for analyzing blockchain transactions. On November 2, he flagged suspicious withdrawals exceeding $106 million from accounts linked to cryptocurrency exchange platforms, though he could not at that time identify the victim.
Continuing to track the funds, he recorded about $27 million in additional movements, lifting his estimate to more than $133 million. He then named Crédit Mutuel Arkéa as the institution involved, while presenting this attribution as provisional.
According to reconstructions published by specialized media, the funds were withdrawn as stablecoins from platforms such as Kraken, Crypto.com, and OKX, then converted into Ether and Monero. These conversions, notably towards Monero, complicate subsequent tracing of the funds.
€118 million diverted?
Crédit Mutuel Arkéa says the incident is “now under control.” According to the Brest-based newspaper Le Télégramme, the incident was reported to the Bank of France.
The banking group also states that the incident has no financial consequences for its customers, claiming to have temporarily suspended certain transfers as soon as the attack was detected.
Some customers reported difficulties performing certain transfers from the group’s applications on November 4. Arkéa says these operations should resume quickly once the remaining verifications and security measures are completed.
The bank does not publicly detail the technical measures undertaken. Neither the nature of the exploited vulnerability, nor the exact scope of affected accounts or systems, nor the strengthening of access controls or collaboration with crypto platforms, are disclosed.
