O'Reilly logo

Learning zANTI2 for Android Pentesting by Miroslav Vitula

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

Uptime guess

Not visible on the preceding screenshot, but still a part of OS detection, Nmap tries to determine the approximate uptime of the remote system. Nmap receives several SYN/ACK TCP packets in a row and checks the headers for a timestamp option. Many operating systems use a simple counter starting with zero at boot time and counting during the uptime. By checking the responses, Nmap can determine these values and print these in the scan log.

The uptime guess is marked as a guess because there are several things that can make it very inaccurate. For instance, some operating systems do not start the counter at zero but initialize it with a random value instead.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required