A malicious iPhone application listed as FOMO on Apple's App Store from Sept. 9 through Sept. 17 contained a module designed to steal mnemonic phrases and private keys, SlowMist Chief Information Security Officer Shan Zhang said. Zhang identified the malware as DarkSword, which exploits memory-corruption vulnerabilities in Safari's WebKit and JavaScriptCore to target crypto assets on iOS versions 13 through 26.5. SlowMist warned that users who downloaded the app should consider all associated mnemonic phrases, private keys and credentials compromised, even if the application was subsequently updated or deleted. Earlier SlowMist and OKX research described a separate App Store application called FomoPeek, whose malicious modules were linked to nearly $580,000 in reported USDT theft, although that total has not been confirmed by a single authoritative primary source. The FOMO report used a different app name from the earlier FomoPeek investigations. Those investigations found malicious components in FomoPeek versions 1.1 and 1.2, released Sept. 9 and Sept. 12, which could bypass iOS sandbox protections, access Keychain data and retrieve files from other applications. Version 1.3, released Sept. 17, removed those components.