Description

Cybersecurity researchers recently discovered a highly advanced Russian botnet operation leveraging DNS misconfigurations and hijacking MikroTik routers in order to spread malware in the form of huge spam campaigns. The research was initiated in November 2024 after a malspam campaign masquerading as DHL Express was discovered. The emails had ZIP attachments comprising obfuscated JavaScript that ran PowerShell scripts that created a connection to a command-and-control server linked to Russian threat actors. Analysis showed that approximately 13,000 MikroTik routers were compromised and running as a coordinated botnet. The infected MikroTik devices used known vulnerabilities as well as likely zero-day exploits through different firmware versions. The routers were converted to SOCKS4 proxies, enabling the attackers to conceal the sources of malicious traffic and stay anonymous. The infrastructure of the botnet facilitated a massive attack, and it supported Distributed Denial-of-Service (DDoS) attacks, credential stuffing, data exfiltration, as well as malware distribution. Most of the routers contained default administrative credentials, thus enabling the attackers to gain control even on the devices that possessed recent firmware updates. The campaign also utilized misconfigured Sender Policy Framework (SPF) records from 20,000 legitimate domains and enabled attackers to evade email security protection. The misconfigurations employed the permissive "+all" flag, which allowed any server to send spoofed email on behalf of these domains. This vulnerability permitted the botnet to deliver malicious payloads successfully, evading conventional anti-spam filters. Organizations are recommended to check for DNS SPF record audits and make sure they are properly configured to prevent these kinds of attacks because the coexistence of DNS vulnerabilities and infected router infrastructure threatens massive security risks.