One of the largest and most notorious spam botnets, known for sending out millions of spam messages every day, has gotten a new communications mechanism that makes it more resilient to take downs, according to security researchers’ analysis. A team of security experts from Dell (NSDQ:Dell) SecureWorks, Damballa Labs and the Georgia Institute of Technology have discovered a new domain name generation algorithm that is part of the Pushdo malware’s back-up command-and-control mechanism. The report, issued by Damballa and Dell SecureWorks, found the malware associated with Pushdo can evade both intrusion detection and prevention systems as well as most antimalware technologies by mimicking legitimate connection attempts to benign websites to confuse signature-based systems.