Five Russian banks that experienced a distributed denial of service (DDoS) attack Sept. 26 believed to have been aimed at starting a bitcoin-related panic had been warned in advance by the General Directorate of Security and Information Protection of the country's Central Bank.

The regulatory body's deputy director, Artyom Sychev, was quoted by The CoinTelegraph as saying the attackers were likely trying to cause panic and destabilization rather than collect a bitcoin ransom. The early warning helped the banks fend off the attack, although they did receive threatening letters in the aftermath.

The CoinTelegraph also quoted a Central Bank official saying that the letters said, "To prevent such acts in the future, the attackers are asking to send only 50 BTC to their Bitcoin wallet.”