computer science

ZMap (software)

ZMap (software) is a computer science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand ZMap (software) rather than just read about it. In short: ZMap is a free and open-source security scanner that was developed as a faster alternative to Nmap. ZMap was designed for information security research and can be used for both white hat and black hat purposes.

Key takeaways

ZMap (software) belongs to computer science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect ZMap (software) to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of ZMap (software) from memory before moving on to harder problems.

Reference excerpt

ZMap is a free and open-source security scanner that was developed as a faster alternative to Nmap. ZMap was designed for information security research and can be used for both white hat and black hat purposes. The tool is able to discover vulnerabilities and their impact, and detect affected IoT devices. Using one gigabit per second of network bandwidth, ZMap can scan the entire IPv4 address space in 44 minutes on a single port. With a ten gigabit connection, ZMap scan can complete a scan in under five minutes.

Operation

ZMap iterates on techniques utilized by its predecessor, Nmap, by altering the scanning method in a few key areas. Nmap sends out individual signals to each IP address and waits for a reply. As replies return, Nmap compiles them into a database to keep track of responses, a process that slows down the scanning process. In contrast, ZMap uses cyclic multiplicative groups, which allows ZMap to scan the same space roughly 1,300 times faster than Nmap. The ZMap software takes every number from 1 to 232-1 and creates an iterative formula that ensures that each of the possible 32-bit numbers is visited once in a pseudorandom order. Building the initial list of numbers for every IP address takes upfront time, but it is a fraction of what is required to aggregate a list of every sent and received probe. This process ensures that once ZMap starts sending probes out to different IPs, an accidental denial of service could not occur because an abundance of transmissions would not converge on one subnet at the same time. ZMap also speeds up the scanning process by sending a probe to every IP address only once by default, whereas Nmap resends a probe when it detects a connection delay or fails to get a reply. This results in about 2% of IP addresses being missed during a typical scan, but when processing billions of IP address, or potential IoT devices being targeted by cyberattackers, 2% is an acceptable tolerance.

Usage ZMap can be used for both vulnerability detection and exploitation. The application has been used for port 443 scans to estimate power outages during Hurricane Sandy in 2013. One of the developers of ZMap, Zakir Durumeric, used his software to determine a computer's online state, vulnerabilities, operating system, and services. ZMap has also been used to detect vulnerabilities in universal plug and play devices and search for weak public keys in HTTPS website logs.

Illustrations

Worked examples

Example 1 — a first encounter with ZMap (software)

Start with the simplest possible case. Write down what ZMap (software) claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to ZMap (software) before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about ZMap (software) ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of ZMap (software)

In research: ZMap (software) appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses ZMap (software) in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: ZMap (software) is common in secondary-school and first-year university syllabi. It links to neighbouring topics Cross-platform free software, Free network management software, Free software programmed in C, so understanding it makes those chapters shorter.
In everyday life: Look for ZMap (software) outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study ZMap (software) in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what ZMap (software) means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain ZMap (software) out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is ZMap (software) in simple terms?

Why does ZMap (software) matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study ZMap (software)?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on ZMap (software).