Description

A malicious campaign targeting Android devices globally utilizes thousands of Telegram bots to infect devices with SMS-stealing malware, stealing one-time 2FA passwords (OTPs) for over 600 services. Zimperium researchers discovered and have been tracking this operation since February 2022, identifying at least 107,000 distinct malware samples. The cybercriminals, motivated by financial gain, likely use infected devices as authentication and anonymization relays. The SMS stealer is distributed via malvertising or Telegram bots that automate victim communication. In the malvertising scenario, victims are led to pages mimicking Google Play, with inflated download counts to create a false sense of trust. On Telegram, bots promise pirated Android applications, asking for the user’s phone number before sharing the APK file. The bot uses this number to generate a new APK, allowing personalized tracking or future attacks. Zimperium reports the operation uses 2,600 Telegram bots to promote various Android APKs, controlled by 13 command and control (C2) servers. Most victims are located in India and Russia, with significant numbers also in Brazil, Mexico, and the United States. The malware transmits captured SMS messages to a specific API endpoint at 'fastsms.su,' a site offering "virtual" phone numbers for anonymization and online authentication. It is likely the infected devices are used by this service without the victims’ knowledge, incurring unauthorized charges and potentially implicating them in illegal activities. To avoid phone number abuse, do not download APK files from outside Google Play, avoid granting risky permissions to unrelated apps, and ensure Play Protect is active on your device.