In December 2018, Slow Fog first discovered and alerted an attacker to a messaging flaw using the Electrum wallet client to force an update prompt to pop up when a user transfers money, inducing users to update and download malware to carry out a currency theft attack. Recently, slow fog technology anti-money laundering (AML) system through continuous tracking found that one of the attackers wallet address bc1qc... p2kny has stolen more than 30 BTCs for six months and has been active recently. Slow Fog alerts Electrum users to update prompts, the new version of Electrum in this update prompt is likely to be false, if installed, please promptly transfer Bitcoin out in another security environment. At the same time, slow fog called on the vast number of cryptocurrencies exchanges, wallets and other platforms of the AML wind control system black and monitor such as the above Bitcoin address. This update tip is a phishing attack by an attacker who exploits a message flaw on the Electrum client and the ElectrumX server, which requires the attacker to deploy the malicious ElectrumX server in advance, and the malicious server is localized by the user's Electrum client (because the Electrum client is a light wallet and the user needs the ElectrumX server to broadcast the transaction). At the time of the madness, malicious ElectrumX servers accounted for as many as 71% of the total, and according to incomplete statistics, hundreds of bitcoins have been stolen in this phishing attack over the past year or so. Although in early 2019 Electrum officials have said they want to adopt some security mechanisms to prevent this kind of update fishing, such as: 1. Patch Electrum client does not display rich text, does not allow arbitrary messages, only strict messages; Patch ElectrumX server implementation detects Sybil Attack (i.e. witch attacks, malicious servers that send phishing messages) and no longer broadcasts them to clients; Implement blacklisting logic to alert malicious servers outside the Electrum client view; Promote social networking sites, websites, and all forms of communication that exist with users, who should always run the latest version and always only install from official sources (electrum.org), access through security protocols (https), and verify GPG signatures in advance. However, many users of Electrum are still in the old version (less than 3.3.4), the old version is still under threat, but slow fog does not rule out that the new version will have a similar threat.