New tool lets single server map entire internet in 45 minutes
Zmap could be boon to analysts, doom for security
Researchers at the University of Michigan have developed a new tool that allows a single server with a gigabit Ethernet port to scan the internet so quickly that it can map 98 per cent of the world's IPv4 connections in under 45 minutes.
Mapping internet nodes is nothing new – companies and researchers have been doing it for years. But the sheer scale of the internet's reach meant that full scans could take months, or require the setting up of a specialized botnet using cloud computing to get the job done. But the new tool, dubbed Zmap, uses smart programming and Ethernet efficiency to get the job done in minutes.
In a paper delivered on Friday to the 22nd USENIX Security Symposium, the team claimed that Zmap operates up to 1,300 times faster than the popular network scanner Nmap, because of "stateless" searching. Whereas Nmap will keep a checklist of internet nodes that have responded to probes, Zmap dumps that time-consuming process and instead encodes the node's details in the packet that gets pinged back.
The tool is also designed to get the absolute most out of Ethernet, and the research paper states that the gigabit connection could be used at 97 per cent efficiency to further speed scanning.
Having access to this kind of speed is going to be a boon to internet analysts, and the team demonstrated how test scans revealed a host of hidden issues. For example, the researchers used Zmap to track the activities of Certificate Authorities (CA) and found the Korean government had misissued 1,300 certificates to schools and educational institutions.
Using different probe modules, the team was also able to map out the adoption of upgraded protocols such as HTTPS and track the speed with which they are being adopted. IT could also track how many such connections were disrupted by "Superstorm" Sandy when it clobbered the US Eastern seaboard last October.
But the researchers warn that Zmap also has serious implications for the security industry if malware propagators cotton on to the technique. They scanned for unpatched machines using a vulnerability in the Universal Plug and Play (UPnP) protocol revealed in January by security researcher HD Moore.
A scan using a module that attempts a discovery handshake via UPnP showed that over 20 per cent of internet-facing hardware was unpatched, and the discovery process for all these machines took less than two hours. A cunning cracker could use such a process to spam out attack code to vulnerable machines, creating vast botnets simply and speedily.
"Given that these vulnerable devices can be infected with a single UDP packet, we note that these 3.4 million devices could have been infected in approximately the same length of time – much faster than network operators can reasonably respond or for patches to be applied to vulnerable hosts," the paper warns. ®
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