Rapid7, a Boston-based vulnerability management and penetration testing company, has acquired Seattle start-up Mobilisafe, which makes cloud-based mobile risk management technology. According to Rapid7, the deal will complement its existing security assessment and management offerings, Metasploit and Nexpose. This is the second mobile security acquisition in recent days. Last week, software security vendor Veracode scooped up Marvin Mobile Security, a California-based company that detects vulnerabilities in the mobile app development process.